Agilent E4438C Service Guide

Service Guide

Agilent Technologies

E4428C/38C ESG Signal Generators

This guide applies to the following signal generator models:

E4428C ESG Analog Signal Generator E4438C ESG Vector Signal Generator

Due to our continuing efforts to improve our products through firmware and hardware revisions, signal generator design and operation may vary from descriptions in this guide. We recommend that you use the latest revision of this guide to ensure you have up-to-date product information. Compare the print date of this guide (see bottom of page) with the latest revision, which can be downloaded from the following website:

http://www.agilent.com/find/esg

Part Number: E4400-90511

Printed in USA

December 2007

Notice

The material contained in this document is provided “as is”, and is subject to being changed, without notice, in future editions. Further, to the maximum extent permitted by applicable law, Agilent d isclaims all warranties, either express or implied with

regard to this manual and to any of the Agilent products to which it pertains, including but not limited to the implied warranties of merchantability and fitness for a particular purpose. Agilent shall not be liable for errors or for incidental or consequential damages in connection with the furnishing, use, or performance of this document or any of the Agilent products to which it pertains. Should Agilent have a written contract with the User and should any of t he contract terms conflict with these ter ms,

the contract terms shall control.

Contents

1. Troubleshooting

Before Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

ESD Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

Getting Started with Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

Troubleshooting Aids. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

ILT-1 Power Supply Failure and Self-Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

ILT-2 A12 CPU Power-On Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

ILT3 Front Panel Display Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8

Symptom: If the Display is Dark. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8

Symptom: If the Display is Bright, but without Characters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11

Symptom: If Hardkeys or Softkeys are Not Funct ioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13

Symptom: If the RPG Knob is Not Functioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15

Symptom: If the Screen Saver is Not Functioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16

Self-Test Failures and Related Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17

Running Self-Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17

Troubleshooting As sembly Level Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21

Power Supplies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21

Self-Tests 1x x for the A10 I/Q Multiplexer (E4438C Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-28

Self-Tests 2xx for the A15 Sampler. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-30

Self-Tests 4xx for the A13 Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-33

Self-Tests 5xx for the A17 Synthesizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-37

Self-Tests 6xx for the A21 YTO Driver. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-40

Self-Tests 7xx for the A16 Frac-N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-43

Self-Tests 8xx for the A18 Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-48

Self-Tests 11xx for the A12 CPU. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-50

Self-Tests 14xx for the A11 Internal Bit Error Rate Analyzer (E4438C Only). . . . . . . . . . . . . . . . . . . 1-52

Self-Tests 15xx for the A9 Digital Demodulator (E4438C Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-54

Self-Tests 16xx for the A7 Baseband Generator (E4438C Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-56

Self-Tests 20xx for the A14 Extended Frequency Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-59

Self-Tests 21xx for the A23 Motherboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-62

Self-Tests 23xx for the A13 Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-64

Troubleshooting Unlocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-68

514 Reference Oven Cold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-68

515 10 MHz Signal Bad. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-68

512 Reference Unlocked . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-69

513 1 GHz Out of Lock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-69

iii

Contents

508 Frac-N Loop Unlock (Option 501, 502, 503, 504). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-69

508 Frac-N Loop Unlock (Option UNJ and Option 506) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 -69

520 Sampler Unlocked (Option UNJ and Option 506) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-69

521 YO Loop Unlocked (Option UNJ and Option 506) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-71

516 Baseband Generator Unlock (E4438C Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-71

623 Demod Unlock (E4438C Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-72

Troubleshooting Unlevels and the RF Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-73

Troubleshooting a Leveling Problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-73

Troubleshooting the AT1 Electronic Attenuator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-78

Troubleshooting the AT1 High-Power Mechanical Attenuator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-81

Troubleshooting Adjustment Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-84

Troubleshooting Analog Bus ADC Calibration Failures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-87

Procedure for Signal Generators with Option 501, 502, 503, 504 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-87

Procedure for Signal Generators with Option UNJ. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-88

Procedure for Signal Generators with Option 506 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-89

Troubleshooting P erformance Test Problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-90

Troubleshooting Harmonic Spurious . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-97

Troubleshooting Harmonic Spurious by Fundamental Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-97

To Verify Harmonic Performance at the RF Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-98

To Verify Harmonic Performance at the Coherent Carrier Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-98

Troubleshooting Non-Harmonic Spurious . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-100

Troubleshooting P hase Noise (Option UNJ and Option 506 Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-102

Troubleshooting P ulse Modulation and LF Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-103

To Verify the Pulse Waveform at the A19 Daught erboard (All Options) . . . . . . . . . . . . . . . . . . . . . . .1-103

To Verify the Pulse Waveform at the A19 Daughterboard (Option 506 Only) . . . . . . . . . . . . . . . . . . .1-105

No Pulse Signal from LF Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-106

Troubleshooting I/Q Calibration (E4438C Only). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-108

Pre-Troubleshooting Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-108

I/Q Calibration Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-109

Contacting Agilent Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-113

Review the Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-113

Contacting Agilent Sales and Service Offices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-113

Important Information Needed by an Agi lent Service Representative . . . . . . . . . . . . . . . . . . . . . . . . .1-113

Returning a Signal Generator for Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-114

Block Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-115

Overall Block Description for Option 501, 502, 503, 504 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-116

Contents

Overall Block Diagram for O ption 501, 502, 503, 504 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-120

Frequency Synthesis Block Description for Option 501, 502, 503, 504 . . . . . . . . . . . . . . . . . . . . . . . 1-122

Frequency Synthesis Block Diagram for Option 501, 502, 503, 504 . . . . . . . . . . . . . . . . . . . . . . . . . 1-124

RF Path Block Description for Option 501, 502, 503, 504 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-126

RF Path Block Diagram for Option 501, 502, 503, 504 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-128

Overall Block Description for Option UNJ and O ption 506 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-130

Overall Block Diagram for O ption UNJ and Option 506 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-134

Frequency Synthesis Block Description for Option UNJ and Option 506 . . . . . . . . . . . . . . . . . . . . . 1-136

Frequency Synthesis Block Diagram for Option UNJ and Option 506 (Page 1 of 2) . . . . . . . . . . . . . 1-138

Frequency Synthesis Block Diagram for Option UNJ and Option 506 (Page 2 of 2) . . . . . . . . . . . . . 1-140

RF Path Block Description for Option UNJ or Option 506. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-142

RF Path Block Diagram for Option UNJ and Option 506 (Page 1 of 2). . . . . . . . . . . . . . . . . . . . . . . 1-146

RF Path Block Diagram for Option UNJ and Option 506 (Page 2 of 2). . . . . . . . . . . . . . . . . . . . . . . 1-148

Analog Modulation Block Description for All Options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-150

Analog Modulation Block Diagram for All Options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-152

Digital Modulation Block Description for All E4438C Options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-154

Digital Modulation Block Diagram for All E4438C Option s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-156

2. Replaceable Parts

Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Order Parts Fast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Save Money with Rebuilt-Exchange Assemblies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Shipping a Defective Assembly Back to Agilent Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

Frequency, Hardware, and Personality Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

Assemblies and Hardware Options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

Assemblies from a Top View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10

Assemblies from a Right-Side View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17

Assemblies of the Front Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19

Assemblies of the Inside Rear Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21

A23BT1 Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22

Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

Inside Front Panel and Fan Cables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

Option 501, 502, 503, 504 Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

Option UNJ Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

Option 506 Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24

Cables for the Inside Front Panel and Fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25

Cables for Option 501, 502, 503, 504 Signal Generators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27

Contents

Overall Cables - Includes Cables for Option UN7, 300, 005, and 001/601 or 002/602) . . . . . . . . . . . .2-27

Front Panel Cables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-30

Standard Cables - Does Not Include Cables for the Front Panel, Option UN7, 300,

or 005. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-31

Only Option UN7, 300, 005, and 001/601 or 002/602 Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-32

Semi-Rigid Cables - Includes the AT1 Electronic Attenuator or the AT1 High-Power Mechanical

Attenuator (Option UNB) with the A28 Reverse Power Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-33

Option 1EM Overall Cables - Includes Cables for Option UN7, 300, 005, and 001/601 or 002/602) . .2-34 Option 1EM Semi-Rigid Cables - Includes the AT1 Electronic Attenuator or the AT1 High-Power

Mechanical Attenuator (Option UNB) with the A28 Reverse Power Protection . . . . . . . . . . . . . . . . . .2-37

Cables for Option UNJ Signal Generators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-38

Overall Cables - Includes Cables for Option UN7, 005, and 001/601 or 002/602 . . . . . . . . . . . . . . . . .2-38

Front Panel Cables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-41

Standard Cables - Does Not Include Cables for the Front Panel, Option UN7, 300, or 005 . . . . . . . . .2-42

Only Option UN7, 300, 005, and 001/601 or 002/602 Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-43

Semi-Rigid Cables - Includes the A21 YTO Driver and the AT1 Electronic Attenuator or the AT1

High-Power Mechanical Attenuator (Option UNB) with A28 Reverse Power Protection . . . . . . . . . . .2-44

Option 1EM Overall Cables - Includes Cables for Option UN7, 005, and 001/601 or 002/602) . . . . . .2-46

Option 1EM Semi-Rigid Cables - Includes the A21 YTO Driver and the AT1 Electronic Attenuator or the

AT1 High-Power Mechanical Attenuator (Option UNB) with A28 Reverse Power Protection. . . . . . .2-49

Cables for Option 506 Signal Generators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-51

Overall Cables - Includes Cables for Option UN7, 005, and 001/601 or 002/602 . . . . . . . . . . . . . . . . .2-51

Front Panel Cables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-54

Standard Cables - Does Not Include Cables for the Front Panel, Option UN7, or Option 005 . . . . . . .2-55

Only Option UN7, 005, and 001/601 or 002/602 Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-57

Semi-Rigid Cables - Includes the A21 YTO Driver and the AT1 High-Power Mechanical Attenuator

(Option UNB) with an A29 DC Blocking Capacitor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-58

Option 1EM Overall Cables - Includes Cables for Option UN7, 005, and 001/601 or 002/602. . . . . . . 2 -60

Option 1EM Semi-Rigid Cables - Includes the A21 YTO Driver and the AT1 High-Power Mechanical

Attenuator (Option UNB) with an A29 DC Blocking Capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-63

Hardware and Other Instrument Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-65

Front Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-66

Disassembled Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-68

Rear-Panel Hardware. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-71

Rear-Panel (Option 1EM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-74

Disassembled AT1 Electronic Attenuator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-77

Disassembled AT1 High-Power Mechanical Attenuator (Option UNB)

and A28 Reverse Power Protection (Option 501, 502, 503, 504 or Option UNJ). . . . . . . . . . . . . . . . . .2-78

Contents

Disassembled AT1 High-Power Mechanical Attenuator (Option 506 Only) . . . . . . . . . . . . . . . . . . . . 2-80

Disassembled A6 Power Supply Shield and Left-Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-81

Disassembled A23 Motherboard and Bottom-Side. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-82

Outside Instrument Covers and Associated Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-83

Inside Instrument Covers and Associated Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-85

Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-86

Accessories. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-86

Documentation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-86

Abbreviations Used in Part Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-87

3. Assembly Replacement

Before You Replace an Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

After Replacing or Repairing an Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

Assemblies That You Can Replace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

Outer and Inner Instrument Covers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Removal Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

A1 Keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8

A2 Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11

A2DS1 Display Backlight. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14

A3 Front Panel Auxiliary Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17

vii

Contents

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-17

A4 Inverter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-19

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-19

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-19

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-19

A5 Hard Drive (E4438C Only). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 -21

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-21

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-21

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-21

A6 Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-24

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-24

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-24

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-24

A7 Baseband Generator (E4438C Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-26

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-26

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-26

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-26

A9 Digital Demodulator (E4438C Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-28

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-28

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-28

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-28

A10 I/Q Multiplexer (E4438C Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-30

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-30

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-30

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-30

A11 Internal Bit Error Rate Analyzer (E4438C Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-32

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-32

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-32

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-32

A12 CPU. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-34

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-34

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-34

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-35

A13 Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-36

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-36

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-36

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-36

viii

Contents

A14 Extended Frequency Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-38

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-38

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-38

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-38

A15 Sampler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-40

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-40

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-40

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-40

A16 Frac-N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-42

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-42

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-42

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-42

A17 Synthesizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-44

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-44

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-44

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-44

A18 Reference. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-46

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-46

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-46

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-46

A19 Daughterboard. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-48

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-48

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-48

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-48

A19 Daughterboard Cable Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-50

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-50

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-50

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-50

A20 Downconverter (E4438C Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-52

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-52

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-52

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-52

A21 YTO Driver and A22 Coupler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-54

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-54

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-54

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-55

A23 Motherboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-56

Contents

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-56

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-56

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-57

A23BT1 Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-59

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-59

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-59

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-59

A24 Line Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 -60

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-60

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-60

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-60

Rear Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-62

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-62

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-62

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-62

A25 Rear Panel Board (E4438C Only). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-64

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-64

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-64

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-64

A26 Rear Panel LVDS Board (Option 1EM — E4438C Only)

and A27 Rear Panel SMB Board (Option 1EM — E4438C Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-66

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-66

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-66

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-66

AT1 High-Power Mechanical Attenuator with A28 Reverse Power Protection. . . . . . . . . . . . . . . . . . . . . . .3-68

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-68

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-68

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-68

AT1 High-Power Mechanical Attenuator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-70

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-70

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-70

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-70

AT1 Electronic Attenuator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-72

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-72

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-72

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-72

A29 DC Blocking Capacitor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-74

Contents

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-74

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-74

Removal Procedure for Option 1EM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-74

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-74

B1 Power Supply Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-76

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-76

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-76

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-76

B2 Small Fan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-78

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-78

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-78

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-78

B3 Daughterboard/Card Cage Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-80

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-80

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-80

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-80

RF Output Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-82

Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-82

Removal Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-82

Removal Procedure for Option 1EM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-82

Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-83

4. Post-Repair Procedures

Performance Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Adjustment Tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8

5. Safety and Re gulatory

Safety Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

General Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

Lithium Battery Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4

Assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5

Notice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6

Certification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7

Contents

xii

Documentation Overview

Installation Guide

User’s Guide

• Safety Information

• Getting Started

• Operation Verification

• Regulatory Information

• E4428C Analog Signal Generator Overview

• E4423C Analog Signal Generator Overview

• Basic Operation

• Basic Digital Operation

• AWGN Waveform Generator

• Analog Modulation

• Digital Signal Interface Module

• Bluetooth Signals

• BERT

• CDMA Digital Modulation

• GPS Modulation

• Multitone Waveform Generator

• Custom Digital Modulation

• Real Time TDMA Formats

• W- CDMA Digital Modulation for Component Test

• W- CDMA Uplink Digital Modulation for Receiver Test

• W- CDMA Downlink Digital Modulation for Receiver Test

• Troubleshooting

Programming Guide

• Getting Started with Remote Operation

• Using IO Interfaces

• Programming Examples

• Programming the Status Register System

• Creating and Downloading Waveform Files

• Creating and Downloading User- Data Files

xiii

SCPI Reference Volum e 1:

• SCPI Basics

• Basic Function Commands

• System Commands

• Analog Commands

• Component Test Digital Commands

Volum e 2:

• Digital Signal Interface Module Commands

• Bit Error Rate Test (BERT) Commands

• Receiver Test Digital Commands

Volum e 3:

• Receiver Test Digital Commands (continued)

Compatibility with E44xxB SCPI Commands

Service Guide

Key and Data Field Reference

• Overview

• E4428C/38C SCPI Commands

• ESG E44xxB Commands

• 8648A/B/C/D Commands

• 8658B, 8657A/B/D/J Programming Codes

• Troubleshooting

• Replaceable Parts

• Assembly Replacement

• Post- Repair Procedures

• Safety and Regulatory

Volum e 1:

• Symbols, Numerics, A- H

Volum e 2:

• Volum e 2: I- Z

xiv

1 Troubleshooting

1-1

Troubleshooting

Before Troubles hooting

Before Troubleshooting

WARNING These troubleshooting instructions are for use by qualified personal only. To avoid electrical shock, do

not perform any troubleshooting unless qualified.

WARNING The opening of covers or removal of parts is likely to expose dangerous voltages. Disconnect the signal

generator from all voltage sources before it is opened.

WARNING The following techniques related to ESD and static-safe workstations should not be used when working

on circuitry with a voltage potential greater than 500 volts.

ESD Information

Protection from Electrostatic Discharge

Electrostatic discharge (ESD) can damage or destroy electronic components. All work on electronic assemblies should be performed at a static-safe workstation using two types of static-safe workstation protection:

• conductive table-mat and wrist-strap combination

• conductive floor-mat and heel-strap combination Both types, when used together, provide a significant level of ESD protection. Of the two, only the table-mat and wrist-strap

combination provides adequate ESD protection when used alone. To ensure user safety, the static-safe accessories must provide at least 1 meg ohm of isolation from ground.

Handling of Electronic Components and ESD

CAUTION Many of the assemblies in this signal generator are very susceptible to damage from electrostatic discharge

(ESD). Perform troubleshooting procedures only at a static-safe workstation and wear a grounding strap.

CAUTION Always handle printed circuit board assemblies by the edges. This will reduce the possibility of ESD damage

to components and prevent contamination of exposed plating.

The possibility of unseen damage caused by ESD is present whenever components are transported, stored, or used. The risk of ESD damage can be greatly reduced by close attention to how all components are handled.

• Perform work on all components at a static-safe workstation.

• Keep static-generating materials at least one meter away from all components.

• Store or transport components is static-shielding containers.

1-2

Troubleshooting

Getting Started with Troubleshooting

Determine the starting point in Table 1-1 to begin troubleshooting.

• Problems should be worked on in the order they are presented in this table.

• Overviews of Self-Test, Frequency Synthesis, RF Path, Analog Modulation, and Digital Modulation are found in this chapter. The information in these overviews may help the reader better understand how the signal generator operates and the function of each assembly. Each overview is also intended to be used to troubleshoot the signal generator.

Table 1-1

If able to run self-test... Go to this section... Run Self-Test “Self-Test Failures and Related Troubleshooting” on page 1-17

and refer to the procedure “Running Self-Test” on page 1-17. If unable to run self-test, check... Go to this section... Power Supply Fail u r e s

A12 CPU Power-on Failures Front Panel Display

or Keyboard Operations If other conditions occur... Go to this section... Unlocked Conditions

Unleveled Conditions Adjustment Problems Performance Test Problems I/Q Calibration Failure

“ILT-1 Power Supply Failure and Self-Test” on page 1-4

“ILT-2 A12 CPU Power-On Test” on page 1-4

“ILT3 Front Panel Display Troubleshooting” on page 1-8

“Troubleshooting Unlocks” on page 1-68

“Troubleshooting Unlevels and the RF Path” on page 1-73

“Troublesho ot ing A djus t ment Probl ems” on page 1-84

“Troubleshooting Performance Test Problems” on page 1-90

“Troubleshooting I/Q Calibration (E4438C Only)” on page 1-108

Troubleshooting Aids

• semi-rigid cable-extender probe

The Agilent E8251-20088 semi-rigid cable-extender probe is used for measuring signals from connectors that are located inside the A19 Daughterboard card-cage.

• ribbon cable extender

The ribbon cable extender needs to be ass embled by the user. It consists of two connector plugs (part number 1252-1010) and approximately eight inches of ribbon cable (part number 8120-22 26 ). The ribb on cable con t ains 2 6 wires; six o f these wires, on either the right or the left side, need to be stripped off before being connected to the plugs.

1-3

Troubleshooting

Getting Started with Troubleshooting

ILT-1 Power Supply Failure and Self-Test

When the signal generator appears to be dead (no display or fan) there is often little evidence that points directly to th e cause. This section provides steps and solutions to typical failure mod e s.

CAUTION Immediately unplug the signal generator from the ac power line if the unit shows any of the following

symptoms:

• Smoke, arcing, or unusual noise from inside the signal generator.

• A circuit breaker or fuse on the main ac power line opens. These potentially serious faults must be corrected before proceeding.

Power Supply LED Checks

❏ Check the front panel LEDs (located next to the LINE switch) for normal operation in both standby and power-on

conditions. Normal operation is indicated as follows:

Table 1-2

Power Switch Yellow LED Green LED

Standby On Off Power-On Off On

— If normal operation is not observed, refer to “Power Supplies” on page 1-21. — If the fan does not operate when the signal generator is powered on, refer to the assembly level troubleshooting section

and verify the fan voltage.

— If the fan operates when the signal generator is powered on,

refer to “ILT-2 A12 CPU Power-On Test” on page 1-4.

ILT-2 A12 CPU Power-On Test

A12 CPU Power-On Test

At power-on, the A12 CP U is designed to complet e a series of operational checks. If all power supply vo ltages are present and the A12 CPU is working correctly, the operational checks are completed. Errors are reported if the A12 CPU has problems identifying other assemblies.

Failure Symptoms

• A2 Display is not functioning

• A12 CPU fails to complete the power-on check

• no LAN activity

• no signal generator control from the front panel

• error message is displayed after power-on

1-4

Getting Started with Troubleshooting

A2 Display is Not Functioning

Refer to ILT3 Front Panel Display Troubleshooting on page 1-8.

A12 CPU Fails to Complete the Power-On Check

1. Turn the power off and remove outer and inner covers.

2. Turn the pow er on and verify that LEDs DS18 through DS25 of the A12 CPU are on. (Refer to Figure 1-1 for the location of LEDs DS18 through DS25 of the A12 CPU.)

• If any of the LEDs are off, turn the signal generator on its side

and check the voltages in Table 1-3 at the A23 Motherboard.

• If the voltages are not present on connector J15 and J5 of the A23 Motherboard,

refer to “Power Supplies” on page 1-21.

• If the voltages are present on connector J15 and J5 of the A23 Motherboard,

turn the power off and remove the A12 CPU.

3. Use a DVM and measure the resistance from J15 to J8 and J5 to J7.

• If the connector is open, change the A23 Motherboard.

Troubleshooting

• If the connector measures good, change the A12 CPU.

1-5

Troubleshooting

Getting Started with Troubleshooting

Figure 1-1 LEDs DS18 through DS25 of the A12 CPU

Table 1-3

Power Supply Voltage (Vdc)

+15 J8-103 J15-103 +14.1 +15.9 DS22

−15 J8-43 J15-43 −15.9 −14.1 DS19 +32 J8-44 J15-44 +31.04 +32.96 DS23 +5.2 J7-59, 60, 119, 120 J5-59, 60, 119, 120 +4.68 +5.72 DS25 +3.4 J7-55, 56, 57, 58,

+9 J8-58 J15-58 +8.73 +9.27 DS20

−6 J8-57 J15-57 −6.36 −5.64 DS21

−5.2 J8-101 J15-101 −5.356 −5.044 DS18

Connector Pins on the Minimum

Value (Vdc)

A12 CPU A23 Motherboard

115, 116, 117, 118

J5-55, 56, 57, 58, 115, 116, 117, 118

+3.298 +3.502 DS24

Maximum Value (Vdc)

LED on top-right corner of A12 CPU

1-6

Troubleshooting

Getting Started with Troubleshooting

Verifying the A12 CPU Power-On Sequence

1. Before verifying the power-on s equen ce, en sure that all eight DIP switches of S1 are in the CLOSED (up) position. (Refer to Figure 1-2 and locate S1 in the upper left-hand corner of the A12 CPU.)

2. Verify the A12 CPU power-on sequence by observing DS1 through DS8. When the power-on sequence is complete, DS1 through DS7 should be on and DS8 should be off.

• If the lights fail to step through the sequence, replace A12 CPU.

(Refer to “A12 CPU” on page 3-34.)

Figure 1-2 S1 and LEDs DS1 through DS8 and DS11 through DS17 of the A12 CPU

Verifying the A5 10 GB Hard Drive

At power on, the hard drive’s file structure is verified.

• If the hard drive is not formatted, the A12 CPU formats it.

• If the file structure is corrupted, the A12 CPU recreates the structure; this may take up to 30 seconds during the power-on sequence.

• If the power-on sequence does not complete, perform the following: a. Turn power off to the signal generator.

b. Disconnect the hard drive’s W26 ribbon cable from P3 of the A12 CPU. c. Turn power on to the signal generator.

— If the power-on sequence does not complete, refer to A12 CPU Fails to Complete the Power-On

Check<$elemparanumonly[Chapter]>-5.

— If the power-on sequence does complete, either the A5 10 GB Hard Drive or the A12 CPU hard drive interface is

bad; these can be isolated by substitution.

1-7

Troubleshooting

Getting Started with Troubleshooting

No LAN Activity

The signal generator supports 10-Base T-LAN. When the instrument is connected to an active LAN, a green LED (DS16) should blink on the A12 CPU; the blinking LED repr esents data communication over the LAN. (Ref er to Fi gure 1- 2 and locate DS16 in the upper middle of the A12 CPU.)

No Instrument Control From the Front Panel

Refer to ILT3 Front Panel Display Troubleshooting<$elemparanumonly[Chapter]>-8.

Error Messages Displayed After Power-On

If error messages are reported after the power-on check is completed, refer to the Error Messages manual for details.

ILT3 Front Panel Display Troubleshooting

The Front Panel Display consists of the following four assembli es:

• A1 Keyboard

• A2 Display (640 x 320 pixel liquid crystal display)

• A3 Front Panel Auxilary Board

• A4 Inverter

The A1 Keyboard contains the front panel hardkeys and softkeys, the power on/off switch along with the standby LED, and the power-on LED. The eight LCD data lines for the A2 Display are routed through the A3 Front Panel Auxilary Board; the A12 CPU controls these eight LCD data lines.

The A4 Inverter turns the A2 Dis play on and off using control lines rout ed throu gh the A3 Front Panel Auxilary Board, which originate on the A12 CPU. The A4 Inverter is used to convert a +5.2 Vdc signal into a 40 kHz 290 Vac signal (approximately); this ac signal is then used to drive the A2 Display.

A2 Display Contrast and Brightness Controls

There are two contrast hardkeys below the A2 Display. The left up-arrow key increases the contras t while the right down-arrow key decreases the contrast.

The A2 Display brightness can be adjusted from 50 (high brightness) to 1 (low brightness) using the RPG, arrow keys, or the numeric keypad.

Softkey Location:

A2 Display Tests

There are two screen tests for the A2 Display: the Black Pixel Screen Test and the White Pixel Screen Test. The Black Pixel Screen Test turns the display dark and the White Pixel Screen Test turns the display bright. To exit either test, press any front panel key.

Softkey Location:

Utility > Display > Brightness

Utility > Display > More (1 or 2)

Symptom: If the Display is Dark

The control lines for the A4 Inverter are routed from the A12 CPU through the A23 Motherboard and the A3 Front Panel Auxilary Board to the A4 CN1 connector. The +5.2 Vdc is routed from the A6 Power Supply through the A23 Motherboard and the A3 Front Panel Auxilary Board to the CN1 connector of the A4 Inverter.

1-8

Figure 1-3 A4 Inverter Connections

Troubleshooting

Getting Started with Troubleshooting

❏ Check that the screen saver is not on.

— Press any front panel key to disable the screen saver.

❏ Check that the signal generator is powered-on and the front-panel green LED is lit.

— If the green LED is not lit, refer to Troubleshooting Assembly Level Problems on page 1-21.

WARNING High voltage is present at the A4 Inverter output (CN2-1). Also, while measuring CN2, be careful of the

fan blades on B1, B2, and B3. Keep hands and fingers away from the fan blades to avoid injury!

❏ Check the voltage, using a DVM, at the A4 Inverter output (CN2-1).

— To access this connector and measure the voltage:

1. Disconnect the front panel assembly from the chassis frame.

2. Slide the front panel display away from the chassis while ensuring that the ribbon cables to the A23 Motherboard stay connected.

1-9

Troubleshooting

Getting Started with Troubleshooting

❏ Check that there is approximately 290 Vac, 40 kHz signal at CN2-1. (This check should be made with the A4 Inverte r

connected to the A2 Display.) — If the signal is present at the A4 Inverter output, replace the A2 Display.

(Refer to “A2 Display” on page 3-11.)

— If the signal is not present at CN2, use a DVM to measure the signals shown in Table 1-4 at CN1 on the A4 Inverter.

Probe CN1 from the top of the connector while it is still connected to the A3 Front Panel Auxilary Board.

Table 1-4

Signal State

CN1-1 5.2 Vdc CN1-3 LIGHT_EN >3 Vdc CN1-4 VDISP Brightness = 50, VDSP < 50 mVdc

Brightness = 1, VDSP = 3 Vdc

— If the signals in Table 1-4 are correct, replace the A4 Inverter.

(Refer to “A4 Inverter” on page 3-19.)

— If any of the signals are incorrect:

a. Using a DVM, measure the signals shown in Table 1-5 at J30 of the A23 Motherboard.

— If the signals in Table 1-5 are correct, replace the A3 Front Panel Auxilary Board.

(Refer to “A3 Front Panel Auxiliary Board” on page 3-17.) — If the 5.2 VD_LCD line is incorrect, refer to the “ILT-1 Power Supply Failure and Self-Test” on page 1-4. — If either the LIGHT_EN or VDISP are incorrect:

a. Using a DVM, measure the signals at J15-37 (LIGHT_EN)

or J15-97 (VDISP) of the A23 Motherboard. — If either signal is incorrect, replace the A12 CPU.

(Refer to “A12 CPU” on page 3-34.)

Table 1-5

Signal State

J30-32 5.2 VD_LCD 5.2 Vdc J30-20 LIGHT_EN >3 Vdc J30-30 VDISP Brightness = 50, VDSP < 50 mVdc

Brightness = 1, VDSP = 3 Vdc

1-10

Troubleshooting

Getting Started with Troubleshooting

Symptom: If the Display is Bright, but without Characters

❏ Check that the signal generator is powered-on and the front panel green LED is lit. If the green LED is not lit, refer to the

Power Supply Troubleshooting section in this manual. Press any front panel key to disable the screen saver. — If the green LED is lit and the display is too bright, try adjusting the contrast controls on the front panel. Refer to

“Symptom: If the Display is Dark” on page 1-8.

— If adjusting the contrast controls has no effect, use an oscilloscope to check the signals in Table 1-6. The pulse-state

signals listed are control, clock, and dat a lin es fo r th e A2 Disp lay. Probe the signals on the back of the ribbon cable on P1 of the A3 Front Panel Auxilary Board.

Table 1-6

Signal State

J1-7 VLCD approximately 21 Vdc J1-4 LCD_EN_L >3 Vdc J1-5 5.2 Vdc J1-8 to 15 Refer to Figure 1-4.

— If the signals in Table 1-6 are correct, replace the A2 Display.

(Refer to “A2 Display” on page 3-11.)

— If the signals are incorrect, use an oscilloscope to check J30 on the A23 Motherboard for signals shown in Table 1-7.

Table 1-7

Signal State

J30-3 VLCD approximately 21 Vdc J30-5 LCD_EN_L >3 Vdc Pulsing Activity LCD_DATA

J1-8 to 15; J30-13, 14, 17, 18, 23, 24, 27, 28; J15-24, 25, 28, 29, 32, 33, 86, 90 Pulsing Activity LCD_CLK

J1-3; J30-4; J15-94 Pulsing Activity LCD_LOAD

J1-2; J30-8; J15-36 Pulsing Activity LCD_FRAME

J1-1; J30-7; J15-93

Figure 1-4 Pulsing Activity LCD_DATA

J1-8 to 15; J30-13, 14, 17, 18, 23, 24, 27, 28; J15-24, 25, 28, 29, 32, 33, 86, 90

Refer to Figure 1-4.

Refer to Figure 1-5.

Refer to Figure 1-6.

Refer to Figure 1-7.

1-11

Troubleshooting

Getting Started with Troubleshooting

Figure 1-5 Pulsing Activity LCD_CLK

J1-3, J30-4, J15-94

Figure 1-6 Pulsing Activity

J1-2, J30-8, J15-36

Figure 1-7 Pulsing Activity

J1-1, J30-7, J15-93

— If the signals in Table 1-7 are correct, replace the A3 Front Panel Auxilary Board.

(Refer to “A3 Front Panel Auxil iary Board” on page 3-17.)

— If any of the signals are incorrect, use an oscilloscope to check J15 on the A23 Motherboard for

signals shown in Table 1-8.

Table 1-8

Signal State

J15-35 VLCD approximately 21 Vd c J15-95 LCD_EN_L >3 Vdc J15-24, 25, 28, 29, 32, 33, 36, 86, 90, 93, 94 Refer to Figure 1-4.

— If the signals in Table 1-8 are incorrect, replace the A12 CPU (Refer to “A12 CPU” on page 3-34).

1-12

Troubleshooting

Getting Started with Troubleshooting

Symptom: If Hardkeys or Softkeys are Not Functioning

The A1 Keyboard contains the switches for the hardkeys and softkeys. These hardkeys and softkeys are arranged in a matrix, as shown in Table 1-9, with the control lines KEYCOLx and KEYROWy on the x and y-axis. When a hardkey or softkey is pressed, one cell of the matrix is activated. The no rmally TTL low KEYROWy, of the active cell, will pulse high and the normally TTL high KEYCOLx, of the active cell, will pulse low. These TTL signals may be measured with an oscilloscope at J32 on the A23 Motherboard. Use Tabl e 1-9 for hardkey and softkey matrix locations.

Figure 1-8 J30 and J32 of the A23 Motherboard

❏ Ensure that the signal generator is powered-on, that the front panel green LED is lit, and that the signal generator is not

being controlled remotely. — If the signal generator is powered-on and the green LED is lit:

a. Press the Local hardkey to place the signal generator in local-control mode. b. Press any suspected defective hardkeys or softkeys while monitoring their corresponding KEYCOLx and

KEYROWy line at J32 of the A23 Motherboard. — If either signal is incorrect, refer to the Table 1-10 and check the signal at J15

on the A23 Motherboard.

J15 is where the signal leaves the A12 CPU.

— If the signal is incorrect at J15, replace the A12 CPU.

(Refer to “A12 CPU” on page 3-34.)

— If both signals at the J32 and J15 conn ectors are correct, replace the A1 Keyboard.

(Refer to “A1 Keyboard” on page 3-8.)

— If the signal generator is powered-on and the green LED is not lit,

refer to “Power Supplies” on page 1-21.

1-13

Troubleshooting

Getting Started with Troubleshooting

Table 1-9 A1 Keyboard Control Lines (KEYCOLx and KEYROWy)

KEYROW0 J32-17

KEYROW1 J32-19

KEYROW2 J32-21

KEYROW3 J32-23

KEYROW4 J32-25

KEYROW5 J32-26

KEYROW6 J32-24

KEYROW7 J32-22

KEYCOL0 J32-1

Softkey 3 NA Cont Up NA NA Mode Menu Mode Sel NA

Softkey 2 Incr/Set Cont Down Ampl Ampl Menu AM Pulse Utility

Softkey 1 Up NA Freq Freq Menu FM/ΦMDig ModCal

Softkey 4NANARight

Softkey 6 NA Local Hold Mod

Softkey 5 NA Return Down

NA NA NA Left Arrow RF On/Off 0 . +/−

Softkey 7NAPresetNANA1 2 3

KEYCOL1 J32-3

KEYCOL2 J32-5

KEYCOL3 J32-7

Arrow

KEYCOL4 J32-9

Help Save Recall Trigger

On/Off NA 7 8 9

Table 1-10 J15 Control Lines (KEYCOLx and KEYROWy)

KEYCOL5 J32-11

456

KEYCOL6 J32-13

KEYCOL7 J32-15

KEYROW0 J32-17 J15-111 KEYCOL0 J32-1 J15-46 KEYROW1 J32-19 J15-51 KEYCOL1 J32-3 J15-47 KEYROW2 J32-21 J15-112 KEYCOL2 J32-5 J15-108 KEYROW3 J32-23 J15-52 KEYCOL3 J32-7 J15-48 KEYROW4 J32-25 J15-53 KEYCOL4 J32-9 J15-109 KEYROW5 J32-26 J15-114 KEYCOL5 J32-11 J15-49 KEYROW6 J32-24 J15-54 KEYCOL6 J32-13 J15-110 KEYROW7 J32-22 J15-55 KEYCOL7 J32-15 J15-50

Figure 1-9 J15 of the A23 Motherboard

1-14

Troubleshooting

Getting Started with Troubleshooting

Symptom: If the RPG Knob is Not Functioning

When the RPG Knob is functioning properly, DS11 on the A12 CPU should blink each time that the RPG knob is rotated.

Figure 1-10 Blinking of DS11 Indicates RPG Knob Activity

• Ensure that the signal generator is powered-on and that the front panel green LED is lit. — If the green LED is lit and the RPG knob is not functioning:

a. Check J32-12 for +5.2 VD_LCD.

— If the voltage is present on J32-12:

a. Press the Frequency hardkey on the front panel. b. Using an oscilloscope, monitor J32-14 and J32-10 while r otating the RPG knob.

The display frequency value should change and both signals at J32-14 and J32-10 should pulse to a TTL high.

— If either of the signals do not pulse to a TTL high, replace the A1 Keyboard.

(Refer to “A1 Keyboard” on page 3-8.)

— If the signals are pulsing to a TTL high:

a. Check the signal at J15-106 and J15-107 of the A23 Motherboard.

— If the signals are pulsing to a TTL high, replace the A12 CPU.

(Refer to “A12 CPU” on page 3-34.)

— If the voltage is not present on J32-12, refer to “Power Supplies” on page1-21.

— If the green LED is not lit, refer to “Power Supplies” on page 1-21.

Figure 1-11 J30 and J32 of the A23 Motherboard

1-15

Troubleshooting

Getting Started with Troubleshooting

Symptom: If the Screen Saver is Not Functioning

The screen saver delay may be set for any integer from 1 to 12 hours. The A12 CPU controls the screen saver by pulling the LIGHT_EN line low.

• Ensure that the signal generator is powered-on and that the front panel green LED is lit. — If the green LED is lit, the delay time has elapsed, and the display hasn’t gone dark:

a. Check the LIGHT_EN signal at J30-20. (Refer to Figure 1-11.)

— If the signal is a TTL low, replace the A4 Inverter.

(Refer to “A4 Inverter” on page 3-19.)

— If the signal is a TTL high:

a. Check J15-37 of the A23 Motherboard. (Refer to Figure 1-9.)

— If the signal is a TTL high, replace the A12 CPU.

(Refer to “A12 CPU” on page 3-34.)

— If the green LED is not lit, refer to “Power Supplies” on page 1-21.

1-16

Troubleshooting

Self-Test Failures and Related Troubleshooting

Overview

The philosophy behind s e lf-t es t i s , “It is better t o pass a defecti ve signal generat or than to fa il a good sign al gener ator.” Self- Test is designed as a diagnostic tool used to check signal generator hardware. Self-tests do not require the signal generator to be calibrated before self-tests will pass. This philosophy implies that some failures will not be detected and reported as bad, but will pass. If the signal generator powers on and self-tests can be run, troubleshooting should always start by running self-tests and resolving reported problems first.

Embedded in the signal generator’s firmware is a group of tests (self-tests) that can be used to evaluate the condition of the circuitry on many of the assemblies. Self-tests check hardware perfo rmance under controlled conditions and comp are test results to predetermined limits. If the results fall within the limits, the signal generator passes. If one or more test results fall outside the limits, the self-test routine evaluates the failures and rep orts the most independent failure.

1. When the signal generator is tested at the factory, self-test limits are loaded into the A12 CPU m emory from devices on each assembly or from fixed files. Most assemblies contain limit information while microcircuit limits must be loaded.

2. When the program runs, latches and DACs are set to a known state.

3. An analog multiplexer routes the detected dc signals from the selected rest node to the A12 CP U.

4. The A12 CPU compares the detected dc level to the test limit. If the detected value is within the limi ts, the A12 CPU reports a pass.

5. If one or more detected values fall outside the limits, the most independent failure is determined and reported .

Independent failures can best be understood by using an example where there are three assemblies in a series: A1 is the first assembly, A2 the second assembly , and A3 the third assembly . A1 output is the input for A2 and A2 output is the input for A3. If A1 output is bad, A2 and A3 outputs are also bad. If A2 output is bad, A3 output is bad.

A file in the signal generator contains this dependency knowledge for the signal generator to use when identi fyin g the m ost independent failure. If A1, A2, and A3 self-tests all fail, the signal generator reports A1 as the most independent failure. If A1 passes, but A2 and A3 fail, self-test reports A2 as the most independent failure. If A2 passes and A3 fails, self-test reports A3 as the most independent failure. If two independent failures o ccur, self-test reports only one failure at a time and re por ts the second failure after the first reported failure is repaired. The troubleshooting procedure is based on the most independent failure and no lower level information is needed. Although not needed for troubleshooting the signal generator, the self-test overhead provides features to view lower level detailed information about the subroutine s and select specific routines to run.

These features include:

• Select/Deselect Test

• Select/Deselect All

• Run Highlighted Tests

• Run Selected Te sts

• View Details When View Details is selected, the measured value, lower, and upper limits are displayed or the highlighted test.

Running Self-Test

1. Press the Utility > Instrument Info/Help Mode > Self Test > Run Complete Self Test.

1-17

Troubleshooting

Self-T est Failures and Related Troubleshooting

In the following table, the first column lists self-test errors, and the second column points to the section that describes assembly-level troubleshooting procedures related to the self test.

Table 1-11 Self-Test Failures and Related Troubleshooting

If the following self-test fails ... Go to this assembly troubleshooting section...

A10 I/Q Multiplexer (E4438C Only)

100 Power Supply 101 Cal Source 102 ExtIn Offset DAC and Switch 103 Path 1&2 and ExtOut 104 Path1 Atten+Su mm in g A mp 105 Path2 Atten+Su mm in g A mp 106 DC-Coupl ed Mode Test 107 Drift Canceller Test 108 IQ Polarity Switch 109 RMS to DC Conv Test

A15 Sampler

200 Power Supply 201 Tuning + Bias Test 203 YO Loop Detector

A13 Output (E442 8C On ly)

400 Ground and PTAT Test 405 Gain Adjustment Test 406 Prelevel Bypass Test 407 Switched Filters Test 408 ALC Reference Test 409 ALC Modulation Test 410 Burst Modulation Test 411 ALC Detector Test

412 Het Band Test

413 Bulk R DAC Test 414 Log Offset Test

“Self-Tests 1xx for the A10 I/Q Multiplexer (E4438C Only)” on page 1-28

“Self-Tests 2xx for the A15 Sampler” on page 1-30

“Self-Tests 4xx for the A13 Output” on page 1-33

A13 Output (E443 8C On ly)

400 Ground and PTAT Test 401 Prelevel Loop Test 402 Quadrature DAC Test 403 VBLO Test 404 Marble Test 405 Gain Adjustment Test 406 Prelevel Bypass Test 407 Switched Filters Test 408 ALC Reference Test 409 ALC Modulation Test 410 Burst Modulation Test 411 ALC Detector Test

412 Het Band Test

413 Bulk R DAC Test 414 Log Offset Test

1-18

“Self-Tests 4xx for the A13 Output” on page 1-33

Self-Test Failures and Related Troubleshooting

Table 1-11 Self-Test Failures and Related Troubleshooting (Continued)

If the following self-test fails ... Go to this assembly troubleshooting section...

Troubleshooting

A17 Synthesizer

500 Power Supply 501 Loop Gain 502 Tuni ng Volt ag e 503 RF Detector 504 FM Inversion

A21 YTO Driver

600 Post Regulators 601 DACs Test 602 PLL Interface 603 FM Driver

A16 Frac-N

700 Power Supply 701 Loop Gain 702 Tuni ng Volt ag e 703 Output Voltage 704 Filter Test 705 F/2 Test 706 FM Path Test

A18 Reference

800 1 GHz Detector 801 Tuni ng Volt ag e 802 AM MUX and DACs 803 FM MUX and DACs

“Self-Tests 5xx for the A17 Synthesizer” on page 1-37

“Self-Tests 6xx for the A21 YTO Driver” on page 1-40

“Self-Tests 7xx for the A16 Frac-N” on page 1-43

“Self-Tests 8xx for the A18 Reference” on page 1-48

A12 CPU

1100 Power Supply

A11 Internal Bit Error Rate Analyzer (E4438C Only)

1400 Power Supply

A9 Digital Demodulator (E4438C Only)

1500 Power Supply

A7 Baseband Generator (E4438C Only)

1600 Host <-> BBG Comm 1601 Apps1 <-> Apps2 Comm 1602 Apps1 <-> SH4 Comm 1603 Apps2 <-> SH4 Comm 1604 Fliegen <-> Apps2 Comm 1605 SRAM Test 1606 SDRAM Test 1607 Paren <-> SH4 Comm 1608 VCO Tune Test 1609 IQ DAC Output Test 1610 PLL Test

“Self-Tests 11xx for the A12 CPU” on page 1-50

“Self-Te sts 14xx for the A11 Internal Bit Error Rate Analyzer (E4438C Only)” on page 1-52

“Self-Tests 15xx for the A9 Digital Demodulator (E4438C Only)” on page 1-54

“Self-Tests 16xx for the A7 Baseband Gener a tor (E4438C Only)” on page 1-56

1-19

Troubleshooting

Self-T est Failures and Related Troubleshooting

Table 1-11 Self-Test Failures and Related Troubleshooting (Continued)

If the following self-test fails ... Go to this assembly troubleshooting section...

A14 Extended Frequency Output

2000 Ground and PTAT Test 2001 Prelevel Loop Test 2002 Quadrature DAC Test 2003 VBLO Test 2004 Marble Test 2005 Gain Adjustment Test 2006 ALC Reference Test 2007 ALC Modulation Test 2008 Burst Modulation Test 2009 ALC Dete ctor Test 2010 Bulk R DAC Test 2011 Log Offset Test

A23 Motherboard

2100 Power Supply 2101 Sweep Diag 2102 LCD Bias

“Self-Tests 20xx for the A14 Extended Fr equency Output” on page 1-59

“Self-Tests 21xx for the A23 Motherboa rd” on page 1-62

1-20

Troubleshooting

Troubleshooting Assembly Level Problems

WARNING Wait 30 second s after unplugging the instrument to allow t he power supplies to discharge before

removing or installing any assemblies.

Power Supplies

The power supply is a switching supply that has an automatic line-voltage and frequency selection. There are no switches to change for 115 Vac or 240 Vac operat ion. The power line fuse is not replaceable. If the fuse opens, the power supply mus t be replaced. To troubleshoot the signal generator’s power supplies, refer to Table 1-12, Table 1-13, Table 1-14, and Table 1-15.

NOTE Many of the power supplies voltages shown in Table 1-12, Table 1-13, Table 1-14,

and Table 1-15 are filtered or regulated on the A23 Motherboard. In some cases, the voltage level may be correct when measured at the A6 Power Supply, but wrong when measured at a destination connector. If this type of situation occurs, it could be due to an open inductor, a shorted capacitor in a filtering circuit, or a bad regulator located on the A23 Motherboard; this would indicate that the A23 Motherboard needs to be changed.

1-21

Troubleshooting

Troubleshooting Assembly Level Problems

Table 1-12

A23 Motherboard test points for: +32 +15

MB LED

+12.5

MB LED

-12.5

+9 VF

Filtered +9

+5.2 VA

Filtered +5.2 VD

MB LED +5.2 VD

A2 Display A3 Front Panel Auxilary Board A6 Power Supply J28-7 J28-25, 36 J28-19, 42 J28-14, 15, 46, 47 J28-14, 15, 46, 47

Slot 1

J11-4 J11-28 J11-2, 27 J1-64 , 65 , 12 9,

130

A7 Baseband Generator (E4438C Only) Slot 2 A9 Digital Demodulator (E4438C Only) Slot 3 A10 I/Q Multiplexer (E4438C O nly ) Slot 4 A11 Internal Bit Error Rate Analyzer (E4438C

J12-4 J12-28 J12-2, 27 J2-64 , 65 , 12 9,

130

J13-4 J13-28 J13-2, 27 J3-64 , 65 , 12 9,

130

J14-28 J14-2 , 27 J4-64, 65, 129,

130 Only) Slot 5 A12 CPU

J15-44 J15-103 J15-58 J15-42 J5-59, 60, 119,

120

A19 Daughterboard J10-83 J10-32, 82 J10-34, 84 J10-30, 31, 80, 81 A20 Downconverter A21 YTO Driver A25 Rear Panel Board or A26 Rear Panel LVDS Board (Option 1EM)

and A27 Rear Panel SMB Board (Option 1EM) AT1 El ec tronic Attenuator J25-1 J25-14 J25-13 J25-15 or AT1 H igh-Power Mechanical Attenuat or

and A28 Reverse Power Protection

J25-1 J22-5

J25-14 J22-3

J25-13 J22-4

J25-15

B1 Power Supply Fan B2 Small Fan B3 Daughterboard/Ca rd Cage Fan

a. MB LED means that an LED for this power supply is visible from the top -side of th e A 23 Motherboard. b. The voltage regulator for this power supply is located on the A 23 Motherboard. c. The voltage for this power supply is filtered on the A 23 Mot h e rboard. d. Slot numbers one through five (where one is on the left) refer to the position of an assembly in the top card-cage of the signal generator when viewed from

the top.

1-22

Table 1-13

Troubleshooting

Troubleshooting Assembly Level Problems

A23 Motherboard test points for: MB LED

+3.4 VDF

A2 Display A3 Front Panel Auxilary Bo ard A6 Power Supply J28-1, 2, 5,

6, 9, 10, 51, 52, 55,

56, 59, 60 Slot 1 A7 Baseband Generator (E4438C Only)

J1-60, 61,

62, 63,

125, 126,

127, 128 Slot 2 A9 Digital Demodulator (E4438C Only)

J2-60, 61,

62, 63,

125, 126,

127, 128 Slot 3 A10 I/Q Multiplexer (E4438C Only)

J3-60, 61,

62, 63,

125, 126,

127, 128 Slot 4 A11 Internal Bit Error Rate Analyzer (E4438C

Only)

Slot 5 A12 CPU

J4-60, 61,

62, 63,

125, 126,

127, 128

J5-55, 56,

57, 58,

115, 116,

117, 118 A19 Daughterboard A20 Downconvert er A21 YTO Driver A25 Rear Panel Board

J36-1 or A26 Rear Panel LVDS Board (Option 1EM)

and A27 Rear Panel SMB Board (Option 1EM) AT1 E le ct ronic Attenuator or AT1 Hi gh-Power Mechanical Attenua tor

and A28 Reverse Power Prote ction B1 Power Supply Fan B2 Small Fan B3 Daughterboard/Card Cage Fan

MB LED

+2.6 VD_1

J1-57, 58, 59, 123, 124

J4-57, 58, 59, 123, 124

MB LED

+2.6 VD_2

J2-57, 58, 59, 123, 124

J3-57, 58, 59, 123, 124

Self-Test Node

+1.8 VD_1

J1-55, 56, 120, 121, 122

Self-Test Node

+1.8 VD_2

J2-55, 56, 120, 121, 122

Self-Test Node

+1.95 VD_1

J1-52, 118

Self-Test Node

+1.95 VD_2

J2-52, 118

a. MB LED means that an LED for this power supply is visible from the top -side of th e A 23 Motherboard. b. The voltage regulator for this power supply is located on the A 23 Motherboard. c. Self-Test Node means that the voltage for this power supply is measured from the analog bus during Self-Test.

1-23

Troubleshooting

Troubleshooting Assembly Level Problems

Table 1-14

A23 Motherboard test points for:

MB LED

-6 VF

Filtered

-6

-15 VF

Filtered

-15

MB LED

-5.2 VF

Filtered

-5.2

+15 STBY

+15 STBY LCD

Filtered +15.2 STBY

+5.2 VD LCD

Filtered +5.2 VD

A2 Display J32-12 A3 Front Panel Auxilary Board J30-31 J30-32 A6 Power Supply J28-38 J28-23 J28-21, 40 J28-34

Slot 1

J11-3 J11-1, 26

A7 Baseband Generator (E4438C Only) Slot 2

J12-3 J12-1, 26 A9 Digital Demodulator (E4438C Only) Slot 3

J13-3 J13-1, 26 A10 I/Q Multiplexer (E4438C O nly ) Slot4

J14-3 J14-1, 26 A11 Internal Bit Error Rate Analyzer (E4438C

Only) Slot 5

J15-57 J15-43 J15-101 J15-102 A12 CPU A19 Daughterboard J10-37, 87J10-36, 86 J10-35, 85 J10-33

Fan +8.5 to +12 Vdc

A20 Downconverter A21 YTO Driver A25 Rear Panel Board or A26 Rear Panel LVDS Board (Option 1EM)

and A27 Rear Panel SMB Board (Option 1EM) AT1 El ectronic Attenuato r or AT1 H igh-Power Mechanical Attenuat or

and A28 Reverse Power Protection B1 Power Supply Fan J33-1 B2 Small Fan J27-1 B3 Daughterboard/Ca rd Cage Fan J29-1

a. MB LED means that an LED for this power supply is visible from the top -side of th e A 23 Motherboard. b. The voltage for this power supply is filtered on the A23 Motherboard. c. The voltage for this power supply is generated by filtering the +15_STBY on the A23 Motherboard. d. Slot numbers one through five (where one is on the left) refer to the position of an assembly in the top card-cage of the signal generator when viewed from

the top.

1-24

Table 1-15

Troubleshooting

Troubleshooting Assembly Level Problems

A23 Motherboard test points for:

+32 VY

Filtered +32 VF

+15 VY

Filtered +15 VF

+5.2 VY

Filtered +5.2 VA

+3.4 VDY

Filtered +3.4 VDF

+5.2 VDY

Filtered +5.2 VD

-15 VY

Filtered

-15 VF

-5.2 VY

Filtered

-5.2 VF

A2 Display A3 Front Panel Auxilary Board A6 Power Supply

Slot 1 A7 Baseband Generator (E4438C Only) Slot 2 A9 Digital Demodulator (E4438C Only) Slot 3 A10 I/Q Multiplexer (E443 8C Only) Slot 4 A11 Internal Bit Error Rate Analyzer (E4438C Only) Slot 5 A12 CPU A19 Daughterboard A20 Downconverter J26-14 J26-13 J26-12 A21 YTO Driver J34-55, 57 J34-54, 56 J34-51 J34-45 J34-44 J34-49 J34-50 A25 Rear Panel Board or A26 Rear Panel LVDS Board (Option 1EM)

and A27 Rear Panel SMB Board (Option 1EM) AT1 Electronic Attenuator or AT1 High -Pow e r Mechanical Attenuator

and A28 Reverse Power Protection B1 Power Supply Fan B2 Small Fan B3 Daughterboard/Car d Ca ge Fa n

a. The voltage for this power supply is filtered on the A23 Mot he r boa rd. b. Slot numbers one through five (where one is on the left) refer to the position of an assembly in the top card-cage of the signal generator when viewed

from the top.

1-25

Troubleshooting

Troubleshooting Assembly Level Problems

If the Amber Standby LED is Not Working

With the power turned off and the signal generator plugged in, the front panel amber standby LED should be on. The amber Standby LED is controlled by a +15 Vdc standby line supplied by the power supply, which is routed through the A23 Motherboard to the front panel.

To troubleshoot the +15 Vdc Standby line, turn the signal gener ator off and follow the signal path. Refer to Table 1-12, Table

1-13, Table 1-14, and Table 1-15.

If the Green Line Power LED is Not Working

When the power switch is turned on, the amber LED goes out and the green LED comes on. The fans start rotating and the front panel display becomes illuminated.

T o troubleshoot, refer to Table 1-12, Table 1-13, Table 1-14, and Table 1-15 and verify the power supply volta ges at J 28 o f t he A23 Motherboard. If the supply voltages are correct, replace the A3 Front Panel Auxilary Board. (Refer to “A3 Front Panel

Auxiliary Board” on page 3-17.)

If the Fans are Not Working

There are three fans located near the front of the instrument that are connected to the A23 Motherboard. The fan control voltages are supplied by th e A6 Power Supply and may be mea sured at J28 of the A23 Motherboard. The fan control voltage range is +8.5 Vdc (at 23 degrees C) to +12.0 Vdc (at 55 degrees C). At higher temperatures, the fan voltage increases along with the rotation of the fan.

T o troubleshoot, disco nnect each fan (one at a time) from the A23 Motherboar d and check the fan voltage. Refer to Table 1-12,

Table 1-13, Table 1 -14, and Table 1-15. If the fan voltage is correct, replace the fan. (Refer to “B1 Power Supply Fan” on page 3-76, “B2 Small Fan” on page 3-78, or “B3 Daughterboard/Card Cage Fan” on page 3-80.)

If the Signal Generator Does Not Power-on and the Power Supply LEDs are Not Working

Each of the power supplies has an LED located on the bottom of the A23 Motherboard. If the power supply is functioning, the green LED is on. Use a voltmeter to measure the supplies on the A23 Motherboard to ensure the voltages meet the pow er supply specifications in the following table.

Power Supply Acceptable Voltage

With the exceptions of the +15 Vdc and the +15 Vdc Standby power supply, each power supply should have a maximum of 10 mV

ripple. The +15 Vdc and the

p-p

+15 Vdc Standby power supply have a maximum ripple specification of 20 mV

. The ripple can be measured using an oscilloscope. If any of the

p-p

supplies LEDs are not on or the measured voltage is less than the acceptable value, one of the assemblies may be loading down the power supply. To find where each power supply is used, refer to Table 1-12, T abl e 1-13, Table 1-14, and

Table 1-15.

To troubleshoot and isolate a defective assembly, turn power off to the signal generator and remove one of the assemblies being biased by the faulty power

+32 Vdc 32.0 ± 0.96 V dc +15 Vdc 15.0 ± 0.45 V dc +15 Vdc Standby 15.0 ± 0.45 Vdc +9.0 Vdc 9.0 ± 0.27 Vdc +5.2 Vdc 5.2 ± 0.16 Vdc +3.3 Vdc 3.3 ± 0.10 Vdc

−6.0 Vdc −6.0 ± 0.18 Vdc

supply.

−15 Vdc −15.0 ± 0.45 Vdc

NOTE It is important to have a minimum number of assemblies removed at one time. The power supply expects to

see a minimum load, otherwise the power supply voltage will increase until an over-voltage condition exists.

Turn power back on to the signal generator and check the suspected faulty power supply. If th e condition is still bad, turn power off to the sign al generato r and re-i nstall the f irst as sembly t hat was r emoved. Rem ove one of t he other as sembli es bein g

1-26

Troubleshooting

Troubleshooting Assembly Level Problems

biased by the faulty power supply and see if the problem is alleviated. Continue this process until the power supply is functioning properly. Replace the last assembly that was removed.

If the Front Panel Power Switch is Not Functioning When the front-panel power s witch is swit ched on, the contro l line (ON/OF F) from the A1 K eyboard is momen tarily ground ed

and the A6 Power Supply is enabled. The ON/OFF signal is routed from the A1 Keyboard through J32-20 t o the A23 Mother board. Cir cuit ry on the A23 Mot herboard uses th e ON/OFF s ignal to genera te the Pwr_On_L. This line is routed to the A6 Power Supply and the A12 CPU; the A6 Power Supply is disabled when the Pwr_On_L line is a TTL high or open.

To troubleshoot

1. Measure J28-34 with a DVM to assure that the +15 Vdc Standby voltage (+15 STBY) is correct.

• If the +15 Vdc Standby voltage is good, use the DVM to measure J32-20 (ON/OFF). The DVM should read approximately +5 Vdc.

a. While monitoring the DVM, depress and hold the front panel power switch.

This grounds the ON/OFF signal and the DVM should read less than a few millivolts.

b. Release the front panel power switch.

The ON/OFF control signal should again be approximately +5 Vdc.

2. With the front panel power switch off, the Pwr_On_L line at J28-32 of the A23 Motherboard should be at approximately +5.8 Vdc; this signal is generated on the A23 Motherboard.

• If the voltage is less than +3.5 Vdc, remove the A6 Power Supply and measure the resistance of the connection from

J28-32 to ground; the impedance should be ≥ 1 Megaohm. — If the impedance is correct, replace the A6 Power Supply.

3. When the front panel power switch is turned on, the Pwr_On_L line goes to < +50 mV.

• If the A1 Keyboard is functioning properly and the Pwr_On_L line is not, replace the A23 Motherboard.

• If the Pwr_On_L line is functioning properly, replace the A6 Power Supply.

1-27

Troubleshooting

Troubleshooting Assembly Level Problems

Self-Tests 1xx for the A10 I/Q Multiplexer (E4438C Only)

Figure 1-12

Table 1-16

Power Supply Voltage (Vdc)

+15 J13-28 14.55 15.45 Main Supply

−15 J13-3 −15.45 −14.55 Main Supply +5.2 J13-2, 27 5.044 5.356 Main Supply

−5.2 J13-1, 26 −5.356 −5.044 Main Supply +5 VD J3-64, 65, 129,

Connector Pins on the A23 Motherboard

130

Minimum Value (Vdc)

5.044 5.356 Main Supply

Maximum Value (Vdc)

Origin

1-28

Troubleshooting

Troubleshooting Assembly Level Problems

100 Power Supply

• If the power supply voltages are good on the connector pins indicated: a. Rem ove the A10 I/Q Multiplexer and measure the resistance of the connection between the appropriate pins of J3/J13

(A23 Motherboard side) and sockets of J3/J13 (A10 I/Q Multiplexer side).

b. If the connection is good, replace the A10 I/Q Multiplexer. (Refer to “A10 I/Q Multiplex er (E4438C Only)” on

page 3-30.)

c. If the connection is bad, replace the A23 Motherboard. (Refer to “A23 Motherboard” on page 3-56.)

• If the supply voltages are bad on any of the connector pins indicate: a. Check the origin of the power supply.

b. If the power supply voltages are good at the origin, replace the A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

c. If the power supply voltages are bad at the origin, troubleshoot the problem using the assembly’s troubleshooting

procedure.

101 Cal Source

• Replace the A10 I/Q Multiplexer.

102 ExtIn Offset DAC and Switch

• Replace the A10 I/Q Multiplexer.

103 Path1&2 and ExtOut

• Replace the A10 I/Q Multiplexer.

104 Path1 Atten+Summing Amp

• Replace the A10 I/Q Multiplexer.

105 Path2 Atten+Summing Amp

• Replace the A10 I/Q Multiplexer.

106 DC-Coupled Mode Test

• Replace the A10 I/Q Multiplexer.

107 Drift Canceller Test

• Replace the A10 I/Q Multiplexer.

108 IQ Polarity Switch

• Replace the A10 I/Q Multiplexer.

109 RMS to DC Conv Test

• Replace the A10 I/Q Multiplexer.

1-29

Troubleshooting

Troubleshooting Assembly Level Problems

Self-Tests 2xx for the A15 Sampler

Figure 1-13

Table 1-17

Power Supply Voltage (Vdc)

+32 J32-7 J10-83 +31.04 +32.96 Main Supply +15 J32-6, 21 J10-32, 82 +14.1 +15.9 Main Supply

−15 J32-2, 17 J10-36, 86 −15.9 −14. 1 Main Supply +9 J32-5, 20 J10-34, 84 +8.73 +9.27 Main Supply +5.2 VD J32-14, 29 J10-35, 85 +4.68 +5.72 Main Supply

1-30

Connector Pins on the Minimum

Value (Vdc) A19 Daughterboard

A23 Motherboard

Maximum Value (Vdc)

Origin

Troubleshooting

Troubleshooting Assembly Level Problems

200 Power Supply

• If the supply voltages are good on the J10 connector pins indicated: a. Turn power off to the signal generator.

b. Remove the A15 Sampler and measure the resistance of he connection between the appropriate J32 and J10 pins.

— If the connection is good, replace the A15 Sampler. (Refer to “A15 Sampler” on page 3-40.) — If the connection is bad, replace the A19 Daughterboard (Refer to “A19 Daughterboard” on page 3-48).

• If the supply voltages are bad on the J10 connector pins indicated: a. Check the origin of the supply.

— If the supply voltages are good at the origin, replace t he A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltages are bad at the origin, troubleshoot the problem using that as sembly's troubleshooting

procedure.

201 Tuning + Bias Test

CAUTION Do not install the A18 Reference or the A15 Sampler with the signal generator pow ered up o r serious damage

to the signal generator may be caused.

• With the signal generator powered up, carefully remove the A15 Sampler from the signal generator.

• Connect a semi-rigid cable-extender probe to P1 and connect a signal analyzer to the probe.

P1 delivers a 1 GHz signal from J3 of the A18 Reference to J1 of the A15 Sampler through W44.

• Check for a 1 GHz signal with a power level ≥ 0dBm. — If the signal is present and at the correct power, replace the A15 Sampler. (Refer to “A15 Sampler” on page 3-40.)

— If the signal is not present or at the correct power:

a. Turn power off to the signal generator. b. Remove t he A18 Reference. c. Measure the resistance of the center pin of W44; it should measure as a short. d. Measure the resistance between the center pin and the shield of W44; it should measure as an open.

— If the cable measures good (as defined in the previous two steps), refer to the A18 Reference troubleshooting

procedure.

— If the cable measures bad, replace the cable.

1-31

Troubleshooting

Troubleshooting Assembly Level Problems

203 YO Loop Detector

CAUTION Do not install the A13 Output with the signal generator powered up or serious damage to the signal generator

may be caused.

• With the signal generator powered up, carefully remove the A15 Sampler from the signal generator.

• Set the signal generator to a frequency of 625 MHz.

• Connect a semi-rigid cable-extender probe to P3 and connect a signal analyzer to the probe.

P3 delivers the YTO output signal from J8 of the A21 YTO Driver to J3 of the A15 Sampler through W37.

• Check for a 5 GHz (± 5 MHz) signal at a power level > −10 dBm. — If the signal is present and at the correct power:

a. Connect a semi-rigid cable-extender probe to P6 and connect a signal analyzer to the probe.

P6 delivers the VCO output signal from J2 of the A16 Frac-N to J6 of the A15 Sampler through W11.

b. Set the signal generator to a frequency of 625 MHz. c. Check for an 859.375 MHz signal at a power level ≥ +5 dBm.

— If the signal is good, replace the A15 S ampler. (Refer to “A15 Sampler” on page 3-40.) — If the signal is bad, refer to the A16 Frac-N troubleshooting procedure.

— If the signal is not present or at the correct power, refer to the A21 YTO Driver troubleshooting procedure.

1-32

Self-Tests 4xx for the A13 Output

Figure 1-14

Troubleshooting

Troubleshooting Assembly Level Problems

Table 1-18

Power Supply Voltage (Vdc)

+15 J12-6, 21 J10-32, 82 +14.1 +15.9 Main Supply

−15 J12-2, 17 J10-36, 86 −15.9 −14.1 Ma in Supply +5.2 J12-14, 29 J10-30, 31, 80, 81 +4.68 +5.72 Main Supply +9 J12-5, 20 J10-34, 84 +8.73 +9.27 Main Supply

−6 J12-3, 18 J10-37, 87 −6.36 −5.64 Main Supply

−5.2 J12-4, 19 J10-35, 85 −5.356 −5.044 Main Supply

Connector Pins on the Minimum

Value (Vdc) A19 Daughterboard

A23 Motherboard

Maximum Value (Vdc)

Origin

1-33

Troubleshooting

Troubleshooting Assembly Level Problems

400 Ground and PTAT Test

• Using a DVM, measure the voltages on J10 (the PTAT voltage is derived from the ± 15 Vdc): — If the supply voltages are good on the J10 connector pins indicated:

a. Turn off the power and remove the A13 Output. b. Measure the resistance of the connection between the appropriate pins of J12 and J10.

— If the connection is good, replace the A13 Output. (Refer to “A13 Output” on page 3-36.) — If the connection is bad, replace the A19 Daughterboard. (Refer to “A19 Daughterboard” on page 3-48.)

— If the supply voltages are bad on any of the J10 connector pins indicated:

a. Check the origin of the supply.

— If the supply voltages are good at the origin, replace t he A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltages are bad at the origin, troubleshoot the problem using that as sembly's troubleshooting

procedure.

401 Prelevel Loop Test (E4438C Only)

CAUTION Do not install the A13 Output with the signal generator powered up or serious damage to the signal generator

may be caused.

• With the signal generator powered up, carefully remove the A13 Output from the signal generator.

• Set the signal generator to a frequency of 900 MHz.

• At J4 of the A13 Output, connect a spectrum analyzer to the A16 Frac-N or A17 Synthesizer RF output and measure the signal; it should be 900 MHz at an amplitude ≥ 5 dBm.

— If the signal is not present or at the correct amplitude, refer to the A16 Frac-N or A17 Synthesizer troubleshooting. — If the signal is present, replace the A13 Output . (Refer to “A13 Output” on page 3-36.)

402 Quadrature DAC Test (E4438C Only)

• Replace the A13 Output.

403 VBLO Test (E4438C O nly)

• Replace the A13 Output.

1-34

404 IQ Test (E4438C Only)

• Measure the Q signal from the A10 I/Q Multiplexer. a. Disconnect the cable from J3 of the A19 Daughterboard and connect it to a DVM.

b. Set the CW frequency to 2 GHz. c. Turn on the I/Q modulation and adjust the Q offset.

Troubleshooting

Troubleshooting Assembly Level Problems

d. Press:

I/Q > I/Q On > I/Q Adjustments > I/Q Adjustments On > Q Offset

e. Rotate the RPG and observe the DVM. The voltage should vary from approximately +0.2 5 Vdc for an offset of 50% to

approximately -0.25 Vdc for an offset of -50%. — If the signal is bad, check it at J10 of the A10 I/Q Multiplexer.

— If the signal is bad at J10, refer to A10 I/Q Multiplexer troubleshooting. — If the signal is good at J10, change the cable.

• Measure the I signal from the A10 I/Q Multiplexer. a. Disconnect the cable from J2 of the A19 Daughterboard and connect it to a DVM.

b. Set the CW frequency to 2 GHz. c. Turn on the I/Q modulation and adjust the I offs et. d. Press:

I/Q > I/Q On > I/Q Adjustments > I/Q Adjustments On > I Offset

e. Rotate the RPG and observe the DVM. The voltage should vary from approximately +0.2 5 Vdc for an offset of 50% to

approximately -0.25 Vdc for an offset of -50%. — If the signal is bad, check it at J9 of the A10 I/Q Multiplexer.

— If the signal is bad at J9, refer to A10 I/Q Multiplexer troubleshooting. — If the signal is good at J9, change the cable.

• If the I and Q signals are good, replace the A13 Output. (Refer to “A13 Output” on page 3-36.)

405 Gain Adjustme nt Test

• Replace the A13 Output.

406 Prelevel Bypass Test

• Replace the A13 Output.

407 Switched filters Test

• Replace the A13 Output.

408 ALC Reference Test

• Replace the A13 Output.

409 ALC Modulation Test

• Replace the A13 Output.

1-35

Troubleshooting

Troubleshooting Assembly Level Problems

410 Burst Modulation Test

• Replace the A13 Output.

411 ALC Detector Test

• Replace the A13 Output.

412 Het Band Test

• Measure the 1 GHz signal from the A18 Reference. a. With the power off, remove the A13 Output and insert a ribbon cable extender into J11 of the A19 Daughterboard.

b. Power on the signal generator and tune to a CW frequency of 200 MHz. c. Using a spectrum analyzer, probe pin 19 of the ribbon cable extender

for a 1 GHz signal with

an amplitude > -20 dBm: — If the signal is present, replace the A13 Output . (Refer to “A13 Output” on page 3-36.)

— If the signal is not present, power down the signal generator and remove the A18 Reference. (Refer to “A18

Reference” on page 3-46.)

d. Using a DVM, measure the resistance between J11-19 and J51-19:

— If the path is open, replace the A19 Daughterboard. (Refer to “A19 Daughterboard” on page 3-48.) — If the path is good (zero ohms), refer to the A18 Reference troubleshooting for the 1 GHz VCO.

413 Bulk R DAC Test

• Replace the A13 Output.

414 Log Offset Test

• Replace the A13 Output.

1. The ribbon cable extender needs to be assembled by the user. It consists of two connector plugs (part number 1252-1010) and approximately eight inches of ribbon cable (part number 8120-2226). The ribbon cable contains 26 wires; six of these w ires need to be stripped off before being connected to the plugs.

1-36

Self-Tests 5xx for the A17 Synthesizer

Figure 1-15

Troubleshooting

Troubleshooting Assembly Level Problems

Table 1-19

Power Supply Voltage (Vdc)

+32 J42-7 J10-83 +31.04 +32.96 Main Supply +15 J42-6, 21 J10-32, 82 +14.1 +15.9 Main Supply

−15 J42-2, 17 J10-36, 86 −15.9 −14. 1 Main Supply +9 J42-5, 20 J10-34, 84 +8.73 +9.27 Main Supply

−6 J42-3, 18 J10-37, 87 −6.36 −5.64 Main Supply

−5.2 J42-4, 19 J10-35, 85 −5.356 −5.044 Main Supply

+5.2 J42-14, 29 J10-30, 31, 80, 81 +4.68 +5.72 Main Supply

Connector Pins on the Minimum

Value (Vdc) A19 Daughterboard

A23 Motherboard

Maximum Value (Vdc)

Origin

1-37

Troubleshooting

Troubleshooting Assembly Level Problems

500 Power Supply

•If the ± 15 V and +5.2 V supplies are good on the connector pins indicated:

a. Turn power off, remove the A17 S ynthesi zer and meas ure the resista nce of the connection between the ap propriate J42

and J10 pins. — If the connection is good, replace the A17 Synthesizer. (Refer to “A17 Synthesizer” on page 3-44.)

— If the connection is bad, replace the A19 Daughterboard. (Refer to “A19 Daughterboard” on page 3-48.)

•If the ± 15 V and +5.2 V supplies are bad on the connector pins indicated:

a. Check the origin of the supply.

— If the supply voltage is good at the ori gin, replace the A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltage is bad at the origin, troubleshoot the problem using that assembly's troubleshooting procedure.

501 Loop Gain

• Replace the A17 Synthesizer.

502 Tuning Voltage

• If the +32 V and +9 V supplies are good on the connector pins indicated:. a. Turn power off, remove the A17 Sy nthesizer , and measure the resistance of the connection between the appropriate J42

and J10 pins. — If the connection is good:

a. Re-insert the A17 Synthesizer. b. Turn power on and check the 10 MHz signal on the A23 Motherboard at J10 pin 99 using an oscilloscope.

The signal should have a period of 100 ns and an amplitude of greater than 1.2 Vp-p. — If the signal is good, replace the A17 Synthesizer. (Refer to “A17 Synthesizer” on page 3-44.)

— If the signal is bad, troubleshoot the A18 Reference. (Refer to “A18 Reference” on page 3-46.)

— If the connection is bad replace the A19 Daughterboard. (Refer to “A19 Daughterboard” on page 3-48.)

• If the +32 V and +9 V supplies are bad on the connector pins indicated:. a. Check the origin of the supply.

— If the supply voltage is good at the origin, replace the A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltage is bad at the origin, troubleshoot the problem using that assembly's troubleshooting

procedure.

1-38

Troubleshooting

Troubleshooting Assembly Level Problems

503 RF Detector

• If the -6 V supply is good on the connector pins indicated: a. Turn power off, remove the A17 S ynthesi zer and meas ure the resista nce of the connection between the ap propriate J52

and J10 pins. — If the connection is good, replace the A17 Synthesizer. (Refer to “A17 Synthesizer” on page 3-44.)

— If the connection is bad, replace the A19 Daughterboard. (Refer to “A19 Daughterboard” on page 3-48.)

• If the -6 V supply is bad on the connector pins indicated: a. Check the origin of the supply.

— If the supply voltage is good at the ori gin, replace the A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltage is bad at the origin, troubleshoot the problem using that assembly's troubleshooting procedure.

504 FM Inversion

• Replace the A17 Synthesizer.

1-39

Troubleshooting

Troubleshooting Assembly Level Problems

Self-Tests 6xx for the A21 YTO Driver

Figure 1-16

Table 1-20

Power Supply Voltage (Vdc)

+32 J1-55, 57 J34-55, 57 +31.04 +32.96 Main Supply +15 J1-54, 56 J34-54, 56 +14.1 +15.9 Main Supply

−15 J1-49 J34-49 −15.9 −14. 1 Main Supply

−5.2 J1-50 J34-50 −5.356 −5.044 Main Supply

+5.2 J1-51 J34-51 +4.68 +5.72 Main Supply +5.2 VD J1-44 J34-44 +4.68 +5.72 Main Supply +3.4 VDY J1-45 J34-45 +3.298 +3.502 Main Supply

1-40

Connector Pins on the Minimum

Value (Vdc)

A21 YTO Driver A23 Motherboard

Maximum Value (Vdc)

Origin

Troubleshooting Assembly Level Problems

600 Post Regulators

• If the +5.2 VD, +3.4 VDY, and ± 15 V supplies are good on the J34 connector pins indicated: a. Remove the W27 ribbon cable from J1 of the A21 YTO Driver.

b. Measure the +5.2 VD, +3.4 VDY, and ± 15 V supplies on the appropriate pins of the W27 ribbon cable.

— If the voltages are good, replace the A21 YTO Driver. (Refer to “A21 YTO Driver and A22 Coupler” on

page 3-54.)

— If the voltages are bad:

a. Remove the W27 ribbon cable from the J34 connector on the A23 Motherboard. b. On W27, measure the resistance between the appropriate pins from one end of the cable to the other.

— If the pins on W27 measure good (indicated as zero ohms), replace the A23 Motherboard. (Refer to “A23

Motherboard” on page 3-56.)

— If the pins on W27 measure bad (i ndicated as infinite ohms), replace the W27 cable.

• If the +5.2 VD, +3.4 VDY, and ± 15 V supplies are bad on the J34 connector pins indicated: a. Check the origin of the supply.

— If the supply voltage is good at the ori gin, replace the A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltage is bad at the origin, troubleshoot the problem using that assembly's troubleshooting procedure.

Troubleshooting

601 DACs Test

• If the +32 V, +5.2 V, and −5.2 V supplies are good on the J34 connector pins indicated: a. Remove the W27 ribbon cable from J1 of the A21 YTO Driver.

b. Measure the +32 V, +5.2 V, and −5.2 V supplies on the appropriate pins of the W27 ribbon cable.

— If the voltages are good, replace the A21 YTO Driver. (Refer to “A21 YTO Driver and A22 Coupler” on

page 3-54.)

— If the voltages are bad:

a. Remove the W27 ribbon cable from the J34 connector on the A23 Motherboard. b. On W27, measure the resistance between the appropriate pins from one end of the cable to the other.

— If the pins on W27 measure good (indicated as zero ohms), replace the A23 Motherboard. (Refer to “A23

Motherboard” on page 3-56.)

— If the pins on W27 measure bad (i ndicated as infinite ohms), replace the W27 cable.

• If the +32 V, +5.2 V, and −5.2 V supplies are bad on the J34 connector pins indicated: a. Check the origin of the supply.

— If the supply voltage is good at the ori gin, replace the A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltage is bad, troubleshoot the problem using that assembly's procedure.

1-41

Troubleshooting

Troubleshooting Assembly Level Problems

602 PLL Interface

• Check for A15 Sampler YO phase lock interference. a. Disconnect the cable from J4 of the A21 YTO Driver. — If test 602 still fails, replace the A21 YTO Driver. (Refer to “A21 YTO Driver and A22 Coupler” on page 3-54.)

— If test 602 passes, troubleshoot the A15 Sampler. (Refer to “A15 Sampler” on page 3-40.)

603 FM Driver

• Measure the FM modulation signal from the A16 Frac-N. a. Disconnect the cable at J3 of the A21 YTO Driver.

b. Select the FM/ϕΜ menu. c. Select the following:

—FM mode —FM Path 1 — FM Dev 100 kHz — FM Source (Internal) — FM Rate 400 Hz — More (1 of 2) >> FM Waveform (Square)

—FM On d. Select Mode On/Off to On. e. Use an oscilloscope and probe the center pin of W28 (the cable that connects to J3 of A21 YTO Driver) to measure a

400 Hz square-wave signal with an amplitude > 2 Vp-p.

— If the signal is good, replace the A21 YTO Driver. (Refer to “A21 YTO Driver and A22 Coupler” on page 3-54.)

— If the signal is bad, turn power off and remove the A15 Sampler and A16 Frac-N.

a. Measure the resistance of the center pin connection between W28 and J14 of the A19 Daughterboard.

This should be a short.

b. Measure the resistance of the connection between the center pin of W28 and ground.

This should be an open. — If the connections are bad, check the W28 cable.

— If the W28 cable is good, replace the A19 Daughterboard. (Refer to “A19 Daughterboard” on page 3-48.) — If the connections are good, troubleshoot the A16 Frac-N.

1-42

Self-Tests 7xx for the A16 Frac-N

Figure 1-17

Troubleshooting

Troubleshooting Assembly Level Problems

Table 1-21

Power Supply Voltage (Vdc)

+32 J42-7 J10-83 +31.04 +32.96 Main Supply +15 J42-6, 21 J10-32, 82 +14.1 +15.9 Main Supply

−15 J42-2, 17 J10-36, 86 −15.9 −14. 1 Main Supply +9 J42-5, 20 J10-34, 84 +8.73 +9.27 Main Supply

−6 J42-3, 18 J10-37, 87 −5.64 −6.36 Main Supply

−5.2 J42-4, 19 J10-35, 85 −5.356 −5.044 Main Supply

+5.2 J42-14, 29 J10-30, 31, 80, 81 +4.68 +5.72 Main Supply

Connector Pins on the Minimum

Value (Vdc) A19 Daughterboard

A23 Motherboard

Maximum Value (Vdc)

Origin

1-43

Troubleshooting

Troubleshooting Assembly Level Problems

700 Power Supply

• If the +5.2 V, +15 V, and −15 V supplies are good on the connector pins indi cated:

a. Turn power off to the signal generator. b. Remove the A16 Frac-N and measure the resistance of th e connection between the appropriate J42 and J10 pins.

— If the connection is good, replace the A16 Frac-N. (Refer to “A16 Frac-N” on page 3-42.) — If the connection is bad, replace the A19 Daughterboard. (Refer to “A19 Daughterboard” on page 3-48.)

• If the +5.2 V, +15 V, and −15 V supplies are bad on the connector pins indicated:

a. Check the origin of the supply.

— If the supply voltage is good at the ori gin, replace the A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltage is bad at the origin, troubleshoot the problem using that assembly's troubleshooting procedure.

701 Loop Gain

• Replace the A16 Frac-N.

702 Tuning Voltage

•If the +32V, −5.2 V, and +9 V supplies are good on the connector pins indicated:

a. Turn power off to the signal generator. b. Remove the A16 Frac-N and measure the resistance of th e connection between the appropriate J42 and J10 pins.

— If the connection is good:

a. Re-insert the A16 Frac-N. b. Turn power on t o t he signal generator. c. Check the 10 MHz signal on the A23 Motherboard at J10 pin 99 using an oscilloscope.

The signal should have a period of 100 ns and an amplitude greater than 1.2 Vp-p. — If the signal is good, replace the A16 F rac-N. (Refer to “A16 Frac-N” on page 3-42.)

— If the signal is bad, troubleshoot the A18 Reference.

— If the connection is bad, replace the A19 Daughterboard. (Refer to “A19 Daughterboard” on page 3-48.)

•If the +32V, −5.2 V, and +9 V supplies are bad on the connector pins indicated:

a. Check the origin of the supply.

— If the supply voltage is good at the origin, replace the A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltage is bad at the origin, troubleshoot the problem using that assembly's troubleshooting procedure.

703 Output Voltage

• Replace the A16 Frac-N.

1-44

Troubleshooting

Troubleshooting Assembly Level Problems

704 Filter Test

• If the -6 V supply is good on the connector pins indicated: a. Turn power off to the signal generator.

b. Remove the A16 Frac-N and measure the resistance of th e connection between the appropriate J42 and J10 pins.

— If the connection is good:

a. Re-insert the A16 Frac-N. b. Remove the A13 Outp ut. c. Turn power on to the signal generator. d. Connect a semi-rigid cable-extender probe to P4 and connect a signal analyzer to the probe; P4 delivers the RF

output of the A16 Frac-N through W41.

T o locate W41, refer to “Semi-Rigid Cables - Includes the A21 YTO Driver and the AT1 Electronic Attenuator

or the AT1 High-Power Mechanical Attenuator (Option UNB) with A28 Reverse Power Protection” on page 2-44.

e. Tune the signal generator to the following frequencies and check for the presence of a signal:

Table 1-22

Options Tune

(MHz)

All 300 300 ± 10 > +5 All 500 500 ± 10 > +5 All 900 900 ± 10 > +5 502/503/504/506 1300 1300 ± 10 > +5 503/504/506 2250 2250 ± 10 > +5 503/504/506 3000 3000 ± 10 > +5

— If these signals are good, replace the A16 Frac-N.

Check (MHz)

Level (dBm)

1-45

Troubleshooting

Troubleshooting Assembly Level Problems

— If these signals are bad, carefully remove the A16 Frac-N with the power on.

a. Connect a semi-rigid cable-extender probe to P1 and connect a signal analyzer to the probe; P1 delivers

the YO input of the A16 Frac-N through W38.

To locate W38, refer to “Semi-Rigid Cables - Includes the A21 YTO Driver and the AT1 Electronic

Attenuator or the AT1 High-Power Mechanical Attenuator (Option UNB) with A28 Reverse Power Protection” on page 2-44.

b. Tune the signal generator to the following frequencies and check for the presence of a signal:

Table 1-23

Options Tune

(MHz)

All 300 4800 ± 300 > −10 All 500 8000 ± 300 > −10 All 900 7200 ± 300 > −10 502/503/504/506 1300 5200 ± 300 > −10 503/504/506 2250 4500 ± 300 > −10 503/504/506 3000 6000 ± 300 > −10

— If these signals are good, replace the A16 Frac-N. (R efer to “A16 Frac-N” on page 3-42.) — If these signals are bad, replace the A21 YTO Driver. (Refer to “A21 YTO Driver and A22 C oupler”

on page 3-54.)

— If the connection is bad, replace the A19 Daughterboard. (Refer to “A19 Daughterboard” on page 3-48.)

• If the -6 V supply is bad on the connector pins indicated: a. Check the origin of the supply.

— If the supply voltage is good at the ori gin, replace the A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

Check (MHz)

Level (dBm)

— If the supply voltage is bad at the origin, troubleshoot the problem using that assembly's troubleshooting procedure.

705 F/2 Test

• Replace the A16 Frac-N.

1-46

706 FM Path Test

• Measure the FM modulation signal from the A18 Reference. a. Turn power off to the signal generator. b. Remove the A16 Frac-N and insert a ribbon cabl e extender

c. Turn power on to the signal generator. d. Select the FM/ϕΜ menu. e. Select the following:

—FM mode —FM Path 1 — FM Dev 100 kHz — FM Source (Internal) — FM Rate 400 Hz — More (1 of 2) >> FM Waveform (Square)

Troubleshooting Assembly Level Problems

into J41 of the A19 Daughterboard.

Troubleshooting

—FM On f. Select Mode On/Off to On. g. Use an oscilloscope and probe pin 11 of the ribbon cable extender to measure a 400 Hz square-wave signal with an

amplitude > 4 Vp-p.

— If the signal is good, replace the A16 F rac-N. (Refer to “A16 Frac-N” on page 3-42.)

— If the signal is bad, turn power off and remove the A18 Reference. (Refer to “A18 Reference” on page 3-46.)

a. Measure the resistance of the connection between J41-11 and J53-11 of the A19 Daughterboard.

This should be a short.

b. Measure the resistance of the connection between J41-11 and ground.

This should be an open. — If the connections are bad, replace the A19 Daughterboard. (Refer to “A19 Daughterboard” on page 3-48.)

— If the connections are good, troubleshoot the A18 Reference.

1-47

Troubleshooting

Troubleshooting Assembly Level Problems

Self-Tests 8xx for the A18 Reference

Figure 1-18

Table 1-24

Power Supply Voltage (Vdc)

+32 J52-7 J10-83 +31.04 +32.96 Main Supply +15 J52-6, 21 J10-32, 82 +14.1 +15.9 Main Supply

−15 J52-2, 17 J10-36, 86 −15.9 −14. 1 Main Supply

−5.2 J52-4, 19 J10-35, 85 −5.356 −5.044 Main Supply

+5.2 J52-14, 29 J10-30, 31, 80, 81 +4.68 +5.72 Main Supply +15 STBY J52-26 J10-33 +14.55 +15.45 Main Supply

Connector Pins on the Minimum

Value (Vdc) A19 Daughterboard

A23 Motherboard

Maximum Value (Vdc)

Origin

1-48

Troubleshooting

Troubleshooting Assembly Level Problems

800 1 GHz Detector

• Replace the A18 Reference.

801 Tuning Voltage

• If the supply voltages are good on the J10 connector pins indicated: a. Turn power off to the signal generator.

b. Remove the A18 Reference and measure the resistance of the connection between the appropriate J52 and J10 pins.

— If the connection is good, replace the A18 Reference. (Refer to “A18 Reference” on page 3-46.) — If the connection is bad, replace the A19 Daughterboard. (Refer to “A19 Daughterboard” on page 3-48.)

• If the supply voltages are bad on the J10 connector pins indicated: a. Check the origin of the supply.

— If the supply voltage is good at the origin, replace the A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltage is bad at the origin, troubleshoot the problem using that assembly's troubleshooting procedure.

802 AM Mux and DACs

• Replace the A18 Reference.

803 FM Mux and DACs

• Replace the A18 Reference.

1-49

Troubleshooting

Troubleshooting Assembly Level Problems

Self-Tests 11xx for the A12 CPU

Figure 1-19

Table 1-25

Power Supply Voltage (Vdc)

+32 J8-44 J15-44 +31.04 +32.96 Main Supply +15 J8-103 J15-103 +14.55 +15.45 Main Supply

−15 J8-43 J15-43 −15.45 −14. 55 Main Supply +9 J8-58 J15-58 +8.73 +9.27 Main Supply

−6 J8-57 J15-57 −6.18 −5.8 2 Main Supply

−5.2 J8-101 J15-101 −5.356 −5.044 Main Supply

+5.2 J7-59, 60, 119, 120 J5-59, 60, 119, 120 +5.044 +5.356 Main Supply +3.4 J7-55, 56, 57, 58,

Connector Pins on the Minimum

Value (Vdc)

A12 CPU A23 Motherboard

115, 116, 117, 118

J5-55, 56, 57, 58, 115, 116, 117, 118

+3.298 +3.502 Main Supply

Maximum Value (Vdc)

Origin

1-50

Troubleshooting

Troubleshooting Assembly Level Problems

1100 Power Supply

• Run the Self-T est to veri fy that the A12 CPU is receiving the following power supplies: +10 V Ref, −6VRef, −5.2 V Ref, and the +9 V Ref.

— If the power supply voltages are correct on the J15 and J5 connector pins indicated:

a. Measure the resistance of the connection between the connectors J8 and J15, or J7 and J5.

— If the connection is good, replace the A12 CPU. (Refer to “A12 CPU” on page 3-34.) — If the connection is bad, replace the A23 Motherboard. (Refer to “A23 Motherboard” on page 3-56.)

— If the power supply voltages are incorrect on the J 15 and J5 connector pins indicated:

a. Check the origin of the power supply.

— If the power supply voltages are good at the origin, replace the A23 Motherboard. (Refer to “A23

Motherboard” on page 3-56.)

— If the power su ppl y vo l tages are bad, troubleshoot the problem using t h e as sem bly’s troubleshooting pr ocedure.

1-51

Troubleshooting

Troubleshooting Assembly Level Problems

Self-Tests 14xx for the A11 Internal Bit Error Rate Analyzer (E4438C Only)

Figure 1-20

Table 1-26

Power Supply Voltage (Vdc)

+15 J14-28 +14.55 +15.45 Main Supply

−15 J14-3 −15.45 −14.55 Main Supply

−5.2 J14-1, 26 −5.356 −5.044 Main Supply

+5.2 VD J4-64, 65 +5.044 +5.356 Main Supply +3.4 VD J4-60, 61, 62, 63 +3.298 +3.502 Main Supply +2.6 VD J4-57, 58, 59 +2.425 +2.575 A23 Motherboard

Connector Pins on the A23 Motherboard

Minimum Value (Vdc)

Maximum Value (Vdc)

Origin

1-52

Troubleshooting Assembly Level Problems

1400 Power Supply

• If the supply voltages are good on the connector pins indicated: a. Turn power off to the signal generator.

b. Remove the A11 Internal Bit Error Rate Analyzer and measure the resistance of the connection between the

appropriate pins of J14/J4, and sockets J14/J4. — If the connection is good, replace the A1 1 In ternal Bit Error Ra te Analyzer. (Refer to “A11 Internal Bit Erro r Rate

Analyzer (E4438C Only)” on page 3-32.)

— If the connection is bad, replace the A23 Motherboard. (Refer to “A23 Motherboard” on page 3-56.)

• If the supply voltages are bad on the connector pins indicated: a. Check the origin of the supply.

— If the supply voltage is good at the origin, replace the A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltage is bad at the origin, troubleshoot the problem using that assembly's troubleshooting procedure.

Troubleshooting

1-53

Troubleshooting

Troubleshooting Assembly Level Problems

Self-Tests 15xx for the A9 Digital Demodulator (E4438C Only)

Figure 1-21

Table 1-27

Power Supply Voltage (Vdc)

+15 J12-28 +14.55 +15.45 Main Supply

−15 J12-3 −15.45 −14.55 Main Supply

−5.2 J12-1, 26 −5.356 −5.044 Main Supply

+5.2 J12-2, 27 +5.044 +5.356 Main Supply +5.2 VD J2-64, 65 +5.044 +5.356 Main Supply +3.4 VD J2-60, 61, 62, 63 +3.298 +3.502 Main Supply +2.6 VD J2-57, 58, 59 +2.425 +2.575 A23 Motherboard

Connector Pins on the A23 Motherboard

Minimum Value (Vdc)

Maximum Value (Vdc)

Origin

1-54

Troubleshooting

Troubleshooting Assembly Level Problems

1500 Power Supply

• If the supply voltages are good on the connector pins indicated: a. Turn power off to the signal generator.

b. Remove the A9 Digital Demodulator and measure the resistance of the connection between the appropriate pins of

J12/J2, and socke t s J12/J2. — If the connection is good, replace the A9 Digital Demodula tor. (Refer to “A9 Digital Demodulator (E4438C

Only)” on page 3-28.)

— If the connection is bad, replace the A23 Motherboard. (Refer to “A23 Motherboard” on page 3-56.)

• If the supply voltages are bad on the connector pins indicated: a. Check the origin of the supply.

— If the supply voltage is good at the origin, replace the A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltage is bad at the origin, troubleshoot the problem using that assembly's troubleshooting procedure.

1-55

Troubleshooting

Troubleshooting Assembly Level Problems

Self-Tests 16xx for the A7 Baseband Generator (E4438C Only)

Figure 1-22

Table 1-28

Power Supply Voltage (Vdc)

+32 J11-4 +31.04 +32.96 Main Supply +15 J11-28 +14.1 +15.9 Main Supply

−15 J11-3 −15.9 −14.1 Main Supply

−5.2 J11-1, 26 −5.356 −5.044 Main Supply

+5.2 J11-2, 27 +4.68 +5.72 Main Supply +3.4 VD J1-60, 61, 62, 63 +3.298 +3.502 Main Supply +2.6 VD J1-57, 58, 59 +2.425 +2.575 A23 Motherboard +1.9 VD J1-52 +1.843 +1.957 A23 Motherboard +1.8 VD J1-55, 56 +1.746 +1.854 A23 Motherboard

Connector Pins on the A23 Motherboard

Minimum Value (Vdc)

Maximum Value (Vdc)

Origin

1-56

Troubleshooting

Troubleshooting Assembly Level Problems

1600 Host <-> BBB Comm

• If the +3.4 VD, +2.6 VD, and +1.9 VD supply voltages are good on the connector pins indicated: a. Turn power off to the signal generator.

b. Remove the A7 Baseband Generator and measure the resistance of the connection between the appropriate pins of J1,

on the A23 Motherboard side, and socket J1, on the A7 Baseband Generator side. — If the connection is good, rep lace the A7 Baseban d Generator. (Refer to “A7 Baseband Generator (E4438C Only)”

on page 3-26.)

— If the connection is bad, replace the A23 Motherboard. (Refer to “A23 Motherboard” on page 3-56.)

• If the +3.4 VD supply voltage is bad on the connector pins indicated: a. Check the origin of the supply.

— If the supply voltage is good at the ori gin, replace the A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltage is bad at the origin, troubleshoot the problem using that assembly's troubleshooting procedure.

• If the +2.6 VD and +1.9 VD supply voltages are bad on the connector pins indicated: a. Replace the A23 Motherboard.

1601 Apps1 <-> Apps2 Comm

• If the +1.8 VD supply voltages is good on the connector pins indicated: a. Turn power off to the signal generator.

b. Remove the A7 Baseband Generator and measure the resistance of the connection between the appropriate pins of J1,

on the A23 Motherboard side, and socket J1, on the A7 Ba seband Gener ator side. — If the connection is good, rep lace the A7 Baseban d Generator. (Refer to “A7 Baseband Generator (E4438C Only)”

on page 3-26.)

— If the connection is bad, replace the A23 Motherboard. (Refer to “A23 Motherboard” on page 3-56.)

• If the supply voltages are bad on the connector pins indicated: a. Check the origin of the supply.

— If the supply voltage is good at the origin, replace the A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltage is bad at the origin, troubleshoot the problem using that assembly's troubleshooting procedure.

1602 Apps1 <-> SH4 Comm

• Replace the A7 Baseband Generator.

1603 Apps2 <-> SH4 Comm

• Replace the A7 Baseband Generator.

1604 Fliegen <-> Apps2 Comm

• Replace the A7 Baseband Generator.

1-57

Troubleshooting

Troubleshooting Assembly Level Problems

1605 SRAM Test

• Replace the A7 Baseband Generator.

1606 SDRAM Test

• Replace the A7 Baseband Generator.

1607 Paren <-> SH4 Comm

• Replace the A7 Baseband Generator.

1608 VCO Tune Test

•If the +32V, ±15 V, and ±5.2 V supply voltages are good on the connector pins indicated: a. Turn power off to the signal generator.

b. Remove the A7 Baseband Generator and measure the resistance of the connection between the appropriate pins of

J11/J1, on the A23 Motherboard side, and socket J11/J1, on the A7 Baseband Generator side. — If the connection is good:

a. Re-insert the A7 Baseband Generator. b. Turn power on t o t he signal generator. c. Check the 10 MHz signal on the A23 Motherboard at J1 pins 26 and 91 using an oscilloscope.

The signal should be 100ns with an amplitude of approximately 1.0 Vp-p or higher. — If the 10 MHz signal is good, replace the A7 Baseband Generator. (Refer to “A7 Baseba nd Generator

(E4438C Only)” on page 3-26.)

— If the 10 MHz signal is bad, troubleshoot the A23 Motherboard and the A7 Baseband Generator.

— If the connection is bad, replace the A23 Motherboard. (Refer to “A23 Motherboard” on page 3-56.)

•If the +32V, ±15 V, and ±5.2 V supply voltages are bad on the connector pins indicated: a. Check the origin of the supply.

— If the supply voltage is good at the ori gin, replace the A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltage is bad at the origin, troubleshoot the problem using that assembly's troubleshooting procedure.

1609 IQ DAC Output Test

• Replace the A7 Baseband Generator.

1610 PLL Test

• Replace the A7 Baseband Generator.

1-58

Self-Tests 20xx for the A14 Extended Frequency Output

Figure 1-23

Troubleshooting

Troubleshooting Assembly Level Problems

Table 1-29

Power Supply Voltage (Vdc)

+15 J22-6, 21 J10-32, 82 +14.1 +15.9 Main Supply

−15 J22-2, 17 J10-36, 86 −15.9 −14.1 Main Supply +9 J22-5, 20 J10-34, 84 +8.73 +9.27 Main Supply

−6 J22-3, 18 J10-37, 87 −6.36 −5.64 Main Supply

−5.2 J22-4, 19 J10-35, 85 −5.356 −5.044 Main Supply

+5.2 J22-14, 29 J10-30, 31, 80, 81 +4.68 +5.72 Main Supply

Connector Pins on the Minimum

Value (Vdc) A19 Daughterboard

A23 Motherboard

Maximum Value (Vdc)

Origin

1-59

Troubleshooting

Troubleshooting Assembly Level Problems

2000 Ground and PTAT Test

• Using a DVM, measure the voltages on J10 (the PTAT voltage is derived from the ± 15 Vdc): — If the supply voltages are good on the J10 connector pins indicated:

a. Turn off the power to the signal generator. b. Remove t he A14 Exte nded Freque ncy Output. c. Measure the resistance of the connection between the appropriate pins of J22 and J10.

— If the connection is good, replace the A14 Extended Frequency Output. (Refer to “A14 Extended Frequency

Output” on page 3-38.)

— If the connection is bad, replace the A19 Daughterboard. (Refer to “A19 Daughterboard” on page 3-48.)

— If the supply voltages are bad on any of the J10 connector pins indicated

a. Check the origin of the supply.

— If the supply voltages are good at the origin, replace t he A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltages are bad at the origin, troubleshoot the problem using that as sembly's troubleshooting

procedure.

2001 Prelevel Loop Test

CAUTION Do not install the A14 Extended Fr equency Output wit h the signal generator powered up or serious damage to

the signal generator may be caused.

• This test checks the Prelevel loop at three frequencies: 4.1 GHz, 5 GHz, and 6 GHz. — If the test fails:

a. Press the b. Press the

View Test Info softkey and use the RPG to highlight this test. View Details softkey to display the failed test frequency.

c. With the signal generator powered on, carefully remove the A14 Extended Frequency Output. d. Set the signal generator to the failed test frequency (either 4.1 GHz, 5 GHz, or 6 GHz). e. Connect a spectrum analyzer to J4 of the A14 Extended Frequency Output; this is the output signal of the

A16 Frac-N.

f. The signal at J4 should be at the failed test frequency with an amplitude ≥−5dBm.

— If the signal is not present or at the correct level, refer to troubleshooting for the A16 Frac-N. — If the signal is present, replace the A14 Extended Frequency Output. (Refer to “A14 Extended Frequency

Output” on page 3-38.)

2002 Quadrature DAC Test

• Replace the A14 Extended Frequency Output.

2003 VBLO Test

• Replace the A14 Extended Frequency Output.

1-60

Troubleshooting Assembly Level Problems

2004 Marble Test

• Measure the Q signal from the A10 I/Q Multiplexer. a. Disconnect the cable at J9 of the A19 Daughterboard and connect it to a DVM.

b. Set the CW frequency to 6 GHz. c. Press:

I/Q > I/Q On > I/Q Adjustments > I/Q Adjustme nts On > Q Offset

d. Rotate the RPG and observe the DVM.

The voltage should vary from approximately +0.30 Vdc for an offset of 50% to approximately -0.20 Vdc for an offset of 50%.

— If the signal is bad, check the signal at J6 of the A10 I/Q Multiplexer.

— If the signal is bad at J6, refer to troubleshooting the A10 I/Q Multiplexer. — If the signal is good at J6, change the cable.

• Measure the I signal from the A10 I/Q Multiplexer. a. Disconnect the cable at J8 of the A19 Daughterboard and connect it to a DVM.

b. Set the CW frequency to 6 GHz. c. Press:

I/Q > I/Q On > I/Q Adjustments > I/Q Adjustme nts On > I Offset

d. Rotate the RPG and observe the DVM.

Troubleshooting

The voltage should vary from approximately +0.25 Vdc for an offset of 50% to approximately -0.25 Vdc for an offset of 50%.

— If the signal is bad, check the signal at J5 of the A10 I/Q Multiplexer.

— If the signal is bad at J5, refer to troubleshooting the A10 I/Q Multiplexer. — If the signal is good at J5, change the cable.

• If both the I and Q signals are good, replace the A14 Extended Frequency Output. (Refer to “A14 Extended Frequency

Output” on page 3-38.)

2005 Gain Adjustment Test

• Replace the A14 Extended Frequency Output.

2006 ALC Reference Test

• Replace the A14 Extended Frequency Output.

2007 ALC Modulation Test

• Replace the A14 Extended Frequency Output.

2008 Burst Modulation Test

• Replace the A14 Extended Frequency Output.

1-61

Troubleshooting

Troubleshooting Assembly Level Problems

2009 ALC Detector Test

• Replace the A14 Extended Frequency Output.

2010 Bulk R DAC Test

• Replace the A14 Extended Frequency Output.

2011 Log Offset Test

• Replace the A14 Extended Frequency Output.

Self-Tests 21xx for the A23 Motherboard

Figure 1-24

1-62

Table 1-30

Power Supply Voltage (Vdc)

+32 J28-27 +31.04 +32.96 Main Supply +15 J28-25, 26 +14.55 +15.45 Main Supply

Connector Pins on the A23 Motherboard

Minimum Value (Vdc)

Maximum Value (Vdc)

Origin

Troubleshooting Assembly Level Problems

Table 1-30

−15 J28-23 −15.45 −14.55 Main Supply +9 J28-19, 42 +8.73 +9.27 Main Supply

−6 J28-38 −6.18 −5.82 Main Supply

−5.2 J28-21, 40 −5.356 −5.044 Main Supply

+5.2 VD J28-14, 15, 46, 47 +5.044 +5.356 Main Supply

Troubleshooting

+3.4 VD J28-1, 2, 5, 6, 9, 10, 51, 52,

55, 56, 59, 60

2100 Power Supply

• If the supply voltages are good on the connector pins indicated, replace the A23 Motherboard. (Refer to “A23

Motherboard” on page 3-56.)

• If the supply voltages are bad on the connector pins indicated: a. Check the origin of the supply.

— If the supply voltage is good at the origin, replace the A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltage is bad at the origin, troubleshoot the problem using that assembly's troubleshooting procedure.

2101 Sweep Diag

• Replace the A23 Motherboard.

2102 LCD Bias

• Use a DVM to probe A23J15-35 for a signal of approximately 21 Vdc. — If the voltage is good, replace the A23 Motherboard. (Refer to “A23 Motherboard” on page 3-56.)

— If the voltage is bad, troubleshoot the A12 CPU.

+3.298 +3.502 Main Supply

1-63

Troubleshooting

Troubleshooting Assembly Level Problems

Self-Tests 23xx for the A13 Output

Figure 1-25

Table 1-31

Power Supply Voltage (Vdc)

+15 J12-6, 21 J10-32, 82 +14.1 +15.9 Main Supply

−15 J12-2, 17 J10-36, 86 −15.9 −14.1 Main Supply +5.2 J12-14, 29 J10-30, 31, 80, 81 +4.68 +5.72 Main Supply +9 J12-5, 20 J10-34, 84 +8.73 +9.27 Main Supply

−6 J12-3, 18 J10-37, 87 −6.36 −5.64 Main Supply

−5.2 J12-4, 19 J10-35, 85 −5.356 −5.044 Main Supply

1-64

Connector Pins on the Minimum

Value (Vdc) A19 Daughterboard

A23 Motherboard

Maximum Value (Vdc)

Origin

Troubleshooting Assembly Level Problems

2300 Ground and PTAT Test

• Using a DVM, measure the voltages on J10 (the PTAT voltage is derived from the ± 15 Vdc): — If the supply voltages are good on the J10 connector pins indicated:

a. Turn off the power and remove the A13 Output. b. Measure the resistance of the connection between the appropriate pins of J12 and J10.

— If the connection is good, replace the A13 Output. (Refer to “A13 Output” on page 3-36). — If the connection is bad, replace the A19 Daughterboard. (Refer to “A19 Daughterboard” on page 3-48).

— If the supply voltages are bad on any of the J10 connector pins indicated:

a. Check the origin of the supply.

— If the supply voltages are good at the origin, replace t he A23 Motherboard. (Refer to “A23 Motherboard” on

page 3-56.)

— If the supply voltages are bad at the origin, troubleshoot the problem using that as sembly's troubleshooting

procedure.

2301 Prelevel Loop Test

Troubleshooting

• Replace the A13 Output.

2302 Quadrature Loop Test

• Replace the A13 Output.

2303 Detector Heater Test

• Replace the A13 Output.

2304 IQ Path Test

• Measure the Q signal from the A10 I/Q Multiplexer. a. Disconnect the cable from J3 of the A19 Daughterboard and connect it to a DVM.

b. Set the CW frequency to 2 GHz. c. Turn on the I/Q modulation and adjust the Q offset. d. Press:

I/Q > I/Q On > I/Q Adjustments > I/Q Adjustments On > Q Offset

e. Rotate the RPG and observe the DVM. The voltage should vary from approximately +0.2 5 Vdc for an offset of 50% to

approximately −0.25 Vdc for an offset of −50%. — If the signal is bad, check it at J10 of the A10 I/Q Multiplexer.

— If the signal is bad at J10, refer to A10 I/Q Multiplexer troubleshooting. — If the signal is good at J10, change the cable.

• Measure the I signal from the A10 I/Q Multiplexer. a. Disconnect the cable from J2 of the A19 Daughterboard and connect it to a DVM.

b. Set the CW frequency to 2 GHz.

1-65

Troubleshooting

Troubleshooting Assembly Level Problems

c. Turn on the I/Q modulation and adjust the I offs et. d. Press:

I/Q > I/Q On > I/Q Adjustments > I/Q Adjustments On > I Offset

e. Rotate the RPG and observe the DVM. The voltage should vary from approximately +0.2 5 Vdc for an offset of 50% to

approximately −0.25 Vdc for an offset of −50%. — If the signal is bad, check it at J9 of the A10 I/Q Multiplexer.

— If the signal is bad at J9, refer to A10 I/Q Multiplexer troubleshooting (page 1-28). — If the signal is good at J9, change the cable.

• If the I and Q signals are good, replace the A13 Output. (Refer to “A13 Output” on page 3-36.)

2305 Prelevel Bypass Test

• Replace the A13 Output.

2306 Switched Filters Test

• Replace the A13 Output.

2307 Gain Adjust Test

• Replace the A13 Output.

2308 ALC Modulation Test

• Replace the A13 Output.

2309 Burst Modulation Test

• Replace the A13 Output.

2310 ALC Detector Test

• Replace the A13 Output.

2311 ALC Closed Loop Test

• Replace the A13 Output.

2312 Detector Logger Test

• Replace the A13 Output.

2313 Het Band Test

• Measure the 1 GHz signal from the A18 Reference. a. With the power off, remove the A13 Output and insert a ribbon cable extender into J11 of the A19 Daughterboard.

b. Power on the signal generator and tune to a CW frequency of 200 MHz. c. Using a spectrum analyzer, probe pin 19 of the ribbon cable extender

for a 1 GHz signal with

an amplitude > −20 dBm: — If the signal is present, replace the A13 Output . (Refer to “A13 Output” on page 3-36.)

1-66

Troubleshooting

Troubleshooting Assembly Level Problems

— If the signal is not present, power down the signal generator and remove the A18 Reference. (Refer to “A18

Reference” on page 3-46.)

d. Using a DVM, measure the resistance between J11-19 and J51-19:

1-67

Troubleshooting

Troubleshooting Unlocks

The phase lock loop refers to that part of the frequency generating circuit used to maintain the phase relationship between the frequency generation loop and a reference frequency. By maintaining the phas e relationship, the frequency accuracy of the signal generator is guaranteed.

To maintain accuracy, the phase lock loop compares the phase of a signal from the reference assembly to the phase of the frequency loop signal. If the two signals are slightly out of phase, the phase comparator circuit adjusts the frequency loop signal until the signals are in phase. If the phase comparator circuit cannot adjust the phase of the frequency lo op signal to agree with the reference signal, the phase comparator rails and generates an unlocked message. The unlock message is immediately displayed on the front panel display.

Troubleshoot multiple Loop unlock messages in the following order:

1. “514 Reference Oven Cold” on page 1-68

2. “515 10 MHz Signal Bad” on page 1-68

3. “512 Reference Unlocked” on page 1-69

4. “513 1 GHz Out of Lock” on page 1-69

5. “508 Frac-N Loop Unlock (Option 501, 502, 503, 504)” on page 1-69 or “508 Frac-N Loop Unlock (Option UNJ and Option 506)” on page 1-69

6. “520 Sampler Unlocked (Option UNJ and Option 506)” on page 1-69

7. “521 YO Loop Unlocked (Option UNJ and Option 506)” on page 1-71

8. “516 Baseband Generator Unlock (E4438C Only)” on page 1-71

9. “623 Demod Unlock (E4438C Only)” on page 1-72

514 Reference Oven Cold

A 514 Reference Oven Cold message indicates that the reference has not been connected to electrical power for 5 minutes. This message appears when the signal generat or is unp l ugg ed or the A18 Refere nce is removed. The messag e is controlled by a timer and should turn off after 5 minutes. This is not a failure unless the message does not go off after 5 minutes.

❏ Check that the message goes away after 5 minutes.

— If the message continues to be displayed after 5 minutes, replace the A18 Reference. (Refer to “A18 Reference” on

page 3-46.)

515 10 MHz Signal Bad

A 515 10 MHz Signal Bad message indicates a problem with the output of the 10 MHz reference oscillator on the A18 Reference.

❏ Check the display for this unlock message.

— If the message is present, replace the A18 Reference. (Refer to “A18 Reference” on page 3-46.)

1-68

Troubleshooting

Troubleshooting Unlocks

512 Reference Unlocked

A 512 Reference Unlocked message indicates a problem with the 10 MHz reference phase-lock loop on the A18 Reference.

❏ Check for and disconnect any external reference signals that are connected to the instrument.

— If the unlock message goes away when the external reference signal has been disconnected, check that the external

reference signal meets the specifications for an external reference.

— If the unlock message is present with the external reference disconnected, replace the A18 Reference. (Refer to “A18

Reference” on page 3-46.)

513 1 GHz Out of Lock

A 513 1GHz Out of Lock message indicates a problem with the 1 GHz phase-lock loop on the A18 Reference. ❏ Check for and disconnect any external reference signals that are connected to the instrument.

— If the unlock message goes away when the external reference signal has been disconnected, check that the external

reference signal meets the specifications for an external reference.

— If the unlock message is present with the external reference disconnected, replace the A18 Reference. (Refer to “A18

Reference” on page 3-46.)

508 Frac-N Loop Unlock (Option 501, 502, 503, 504)

A 508 Frac-N Loop Unlock message indicates a problem with the Voltage Control Oscillator's (VCO) phase-lock loop on the A17 Synthesizer.

❏ Check the 10 MHz signal on the A23 Motherboard at J10 pin 99 using an oscilloscope.

The signal should have a period of 100 ns and an amplitude of greater than 1.2 Vp-p. — If the signal is good, replace the A17 Synthesizer. (Refer to “A17 Synthesizer” on page 3-44.)

— If the signal is bad, troubleshoot the A18 Reference. (Refer to “Self-Tests 8xx for the A18 Reference” on page 1-48.)

508 Frac-N Loop Unlock (Option UNJ and Option 506)

A 508 Frac-N Loop Unlock message indicates a problem with the Voltage Control Oscillator's (VCO) phase-lock loop on the A16 Frac-N.

❏ Check the 10 MHz signal on the A23 Motherboard at J10 pin 99 using an oscilloscope.

The signal should have a period of 100 ns and an amplitude of greater than 1.2 Vp-p. — If the signal is good, replace the A16 F rac-N. (Refer to “A16 Frac-N” on page 3-42.)

— If the signal is bad, troubleshoot the A18 Reference. (Refer to “Self-Tests 8xx for the A18 Reference” on page 1-48.)

520 Sampler Unlocked (Option UNJ and Option 506)

A 520 Sampler Unlocked message indicates a problem with the Voltage Control Oscillator's (VCO) phase- lock lo op on th e A15 Sampler.

❏ Run self-tests.

1-69

Troubleshooting

Troubleshooting Unlocks

— If self-tests fail, troubleshoot the problem reported. — If self-tests pass:

1. Turn power on t o t he signal generator.

2. Remove the A15 Sampler.

3. Connect a signal analyzer to the A15 Sampler J1 input (W44 cable that comes from the A18 Reference).

4. Check for the presence of a 1 GHz signal with a power level of 0 dBm or greater. — If the signal is good on W44 cable connector for J1, replace the A15 Sampler. (Refer to “A15 Sampler” on

page 3-40.)

— If the signal is bad on the W44 cable connector for J1:

a. Turn power off to the signal generator. b. Remove the A18 Reference. (Refer to “A18 Reference” o n page 3-46.) c. Ohm the cable between the center pins (a short should be measured) and between the center pin and

shielding (an open should be measured) at J3 of the A18 Reference and J1of the A15 Sampler. — If the cable is good, troubleshoot the A18 Reference. (Refer to “Self-Tests 8xx for the A18 Reference”

on page 1-48.)

— If an open is measured between the center pins or a short between the center pins and the shielding,

replace the W44 cable.

1-70

Troubleshooting Unlocks

521 YO Loop Unlocked (Option UNJ and Option 506)

A 521 YO Loop Unlocked message indicates a problem with the YO phase detector on the A15 Sampler.

1. Turn power on t o t he signal generator.

2. Remove the A15 Sampler.

3. Set the signal generator to 525 MHz.

4. Using a signal analyzer, check for the presence of signals as shown in Table 1-32:

• If all signals are good, replace the A15 Sampler. (Refer to “A15 Sampler” on page 3-40.)

• If any signal is bad, troubleshoot one of the following two assemblies: — either the A21 YTO Driver (Refer to “Self-Tests 6xx for the A21 YTO Driver” on page 1-40.)

— or the A16 Frac-N (Refer to “Self-Tests 7xx for the A16 Frac-N” on page 1-43.)

Table 1-32

Troubleshooting

Signal Generator Output

(MHz)

Tune A15J3

525 4200 796.875 750 6000 644.53 500 8000 593.75

Output of A21 YTO Driver

Sampler End of W37

(> −20 dBm, ±10 MHz)

Output of A15 Sampler

Sampler End of W11

A15J6 (> +5 dBm, ±10 MHz)

516 Baseband Generator Unlock (E4438C Only)

A 516 Baseband Generator Unlock message indicates a problem with the V oltage Control Oscillator's (VCO) phase-lock loop on the A7 Baseband Generator.

❏ Check the 10 MHz signal on the A23 Motherboard at J1 pins 26 and 91 using an oscilloscope.

The signal period should be 100 ns with an amplitude of approximately 1.0 Vp-p or greater. — If the 10MHz signal is good, replace the A7 Baseband Generator. (Refer to “A7 Baseband Generator (E4438C Only)”

on page 3-26.)

— If the signal is not present, troubleshoot one of the following two assembli es:

— either the A23 Motherboard (Refer to “Self-Tests 21xx for the A23 Motherboard” on page 1-62.) — or the A18 Reference (Refer to “Self-Tests 8xx for the A18 Reference” on page 1-48.)

1-71

Troubleshooting

Troubleshooting Unlocks

623 Demod Unlock (E4438C Only)

A 623 Demod Unlock message indicates a problem with the Voltage Control Oscillator's (VCO) phase-lock lo op on th e A9 Digital Demodulator.

❏ Check the 10 MHz signal on the A23 Motherboard at J2 pins 26 and 91 using an oscilloscope.

The signal period should be 100 ns with an amplitude of approximately 1.0 Vp-p or greater. — If the signal is good, replace the A9 Digital Demodulator. (Refer to “A9 Digital Demodulator (E4438C Only)” on

page 3-28.)

— If the signal is bad, troubleshoot one of the following two assemblies:

— either the A23 Motherboard (Refer to “Self-Tests 21xx for the A23 Motherboard” on page 1-62.) — or the A18 Reference (Refer to “Self-Tests 8xx for the A18 Reference” on page 1-48.)

1-72

Troubleshooting

Troubl eshooting Unlevels and th e RF Path

Troubleshooting Unlevels and the RF Path

Depending on the signal generator’s frequency range and option selection, there are either one or two output boards used in the RF path:

• Signal generators with Option 501, 502, 503, 504, and Option UNJ contain either the: — A13 Output (Option 501, 502, 503, 504 or Option UNJ)

— or the A13 Output (Option UNB)

• Signal generators with Option 506 contain both the: — A13 Output (Option UNB)

— and the A14 Extended Frequency Output (Option 506)

On the output boards, a leveled output power is obtained by comparing a detected voltage with a reference voltage. The reference voltage is generated using DACs on the output boards. The detected voltage is g enerated by co upling o f f a po rtion of the RF output signal and converting it to dc using detector diodes. When the reference and detected levels are the same, the integrated output level remains constant. When the reference and detected levels are not the same, the integrator output ramps either up or down to increase or decrease the detected level. If the integrator can not achieve a match between the detected voltage and the reference voltage, an unleveled annunciator is displayed.

Each output board has an Automatic Leveling Control (ALC) circuit which consists of a detector and two modulator diodes. The A13 Output controls the power level for frequencies 4 GHz and below and the A14 Extended Frequency Output (Option 506) controls the power level for frequencies above 4 GHz and ≤ 6 GHz.

The RF path must provide a minimum power level to the ALC loop in order for the ALC loop to work properly and this minimum required power is slightly higher than the maximum-leveled power.

Troubleshooting a Leveling Problem

NOTE Before proceeding to troubleshoot with this section, run a full self-test and correct any reported failures and

unlock problems. (Refer to “Self-Test Failures and Related Troubleshooting” on page 1-17 and

“Troubleshooting Unlocks” on page 1-68.)

❏ Check the RF path power level against the values in Table 1-33.

Table 1-33

Frequencies Standard Power Option UNB

250 kHz to 1 GHz +13 dBm +17 dBm > 1 GHz to 3 GHz +10 dBm +16 dBm > 3 GHz to 4 GHz +7 dBm +13 dBm > 4 GHz to 6 GHz (Option 506) N/A +10 dBm

— If the instrument cannot achieve the maximum power levels listed in Table 1-33, perform the ALC Calibration and the

Power Level Accuracy, Hig h Power Calibration. — If these adjustments fail or the instrument still cannot achieve the maximum power levels listed in Table 1-33,

proceed to “Troubleshooting the RF Path” on page 1-75.

1-73

Troubleshooting

Troubleshooting Unlevels and the RF Path

❏ Check for an Unleveled Annunciator

— If the Unleveled Annunciator is on:

1. Check that the signal generator's amplitude is not set higher than the maximum level specified on the Specifications data sheet.

— If the unleveled indication turns off after resetting the amplitude, the signal generator is operating correctly.

2. Check that the signal generator's RF output is ter m inated into 50 ohms. — If the unleveled indication turns off after terminating the RF output into 50 ohms, the signal generator is

operating correctly.

— If the Unleveled Annunciator remains on:

1. Use a spectrum analyzer to check the RF signal level at the RF Output connector. — Signal Generator Setup

a. Set

ALC On/Off to Off

b. Set

Amplitude to +25 dBm

c. Set

Modulation to Off

d. Set

RF On/Off to On

e. Set

Sweep to Frequency

f. Set

Sweep Type to Step

g. Set

Start Frequency to 250 kHz

h. Set

Stop Frequency to 1 GHz

i. Set

Number of Points to 500

— Spectrum Analyzer Setup

a. Set

Start Frequency to 225 kHz

b. Set

Stop Frequency to 1.25 GHz

c. Set

Reference Level to +30 dBm

d. Set

Display to Max Hold

2. Connect the RF output of the signal generator to the spectrum analyzer.

3. Measure and record the minimum power level.

4. Set the signal generator and spectrum analyzer start/stop frequencies to the next start/stop frequencies in Table 1-34.

Table 1-34

Signal Generator Spectrum Analyzer

1-74

Start Stop Start Stop 1 GHz 3 GHz 999 MHz 3.1 GHz 3 GHz 4 GHz 2.99 GHz 4.1 GHz

4.000000001 GHz 6 GHz 4 GHz 6.1 GHz

Troubleshooting

Troubl eshooting Unlevels and th e RF Path

5. Measure and record the minimum power l evel at each start/stop frequency. — If any of the frequency ranges do not produce power levels equal to the maximum leveled power shown in

T a b le 1-33, set the signal generator to the frequency with the lowest power level and measure the power with a

power mete r. — If the power level is low, troubleshoot the RF path before proceeding.

— If the RF signal levels are good, turn ALC On and set the signal generator to maximum-leveled power.

Note the frequencies where the unleveled condition occur. Later, when troubleshooting in ALC Off mode, the unleveled indication is turned off.

For each of the unleveled conditions listed, always start with the signal generator s et to the following settings.

a. Set b. Set c. Set d. Set e. Set

ALC Mode to ALC Off Amplitude to +25 dBm Attenuator Hold Mode to On RF On/Off to On Modulation to Off

Troubleshooting the RF Path

Depending on the frequency range that an unlevel is occurring, refer to one of the following:

• Unleveled or Low Power for Frequencies ≥ 250 kHz and < 250 MHz on page 1-75.

• Unleveled or Low Power for Frequencies ≥ 250 MHz and ≤ 4 GHz on page 1-76.

• Unleveled or Low Power for Frequencies > 4 GHz and ≤ 6 GHz (Option 506 Only) on page 1-77.

Unleveled or Low Power for Frequencies ≥ 250 kHz and < 250 MHz

NOTE Before proceeding to troubleshoot with this section, run a full self-test and correct any reported failures and

unlock problems. (Refer to “Self-Test Failures and Related Troubleshooting” on page 1-17 and

“Troubleshooting Unlocks” on page 1-68.)

1. Set the signal generator to the frequency where the signal generator is unleveled.

2. With the signal generator powered on, carefully remove the A13 Output.

3. Use a semi-rigid cable extender and connect a spectrum a nalyzer to the A1 6 Frac-N or A17 Synthesizer RF output at J4 of the A13 Output and measure the power level.

The amplitude of the signal at J4 should be ≥ 5 dBm and the RF frequency at J4 is determined by the following equation:

J4 Frequency = 1 GHz - Front Panel RF Frequency

• If the J4 signal is good, replace the A13 Output.

• If the J4 signal is bad and the instrument is an:

— Option 501, 502, 503, 504, replace the A17 Synthesizer.

1-75

Troubleshooting

Troubleshooting Unlevels and the RF Path

— Option UNJ or Option 506, check the signal leaving the YIG oscillator.

The YIG frequency is determined by the equation:

YIG Frequency = (1 GHz - Front Panel RF Frequency) * 8

— If the signal is good out of the YIG, replace the A16 Frac-N. — If the signal is bad out of the YIG, replace the A21 YTO Driver.

— Option 506, check the signal at the input of the A22 Coupler.

— If the signal is good, replace the A22 Coupler. — If the signal is bad, check the signal leaving the YIG oscillator.

The YIG frequency is determined by the equation:

YIG Frequency = (1 GHz - Front Panel RF Frequency) * 8

— If the signal is good, replace the semi-rigid cable (W54) between the YIG Oscillator and the input of the

A22 Coupler

— If the signal is bad, replace the A21 YTO Driver.

Unleveled or Low Power for Frequencies ≥ 250 MHz and ≤ 4 GHz

NOTE Before proceeding to troubleshoot with this section, run a full self-test and correct any reported failures and

unlock problems. (Refer to “Self-Test Failures and Related Troubleshooting” on page 1-17 and

“Troubleshooting Unlocks” on page 1-68.)

1. Set the signal generator to the unleveled frequency.

2. With the signal generator powered on, carefully remove the A13 Output.

3. Use a semi-rigid cable extender and connect a spectrum a nalyzer to the A1 6 Frac-N or A17 Synthesizer RF output at J4 of the A13 Output.

The signal at J4 should be the same f requ ency that the signal generator is set to and the amplitude at J4 should be ≥ 0 dBm.

• If the J4 signal is good, replace the A13 Output.

• If the J4 signal is bad and the instrument is an:

— Option 501, 502, 503, 504, change the A17 Synthesizer. — Option UNJ, check the signal leaving the YIG Oscillator.

The YIG frequency will be higher that the front panel frequency. It is divided down with the divisor being dependent on the front panel frequency.

— If the signal is good, change the A16 Frac-N. — If the signal is bad out of the YIG, change the A21 YTO Driver

— Option 506, check the signal at the input of the A22 Coupler.

— If the signal is good, replace the A22 Coupler. — If the signal is bad, check the signal leaving the YIG Oscillator.

1-76

Troubleshooting

Troubl eshooting Unlevels and th e RF Path

The YIG frequency will be higher than the front panel frequency. It is divided down with the divisor being dependent on the front panel frequency.

— If the signal is good, replace the semi-rigid cable (W54) between the YIG Oscillator and the input of the

A22 Coupler. (Refer to “Semi-Rigid Cables - Includes the A21 YTO Driver and the AT1 High-Power

Mechanical Attenuator (Option UNB) with an A29 DC Blocking Capacitor” on page 2-58.)

— If the signal is bad, change the A21 YTO Driver.

Unleveled or Low Power for Frequencies > 4 GHz and ≤ 6 GHz (Opti on 506 Only)

NOTE Before proceeding to troubleshoot with this section, run a full self-test and correct any reported failures and

unlock problems. (Refer to “Self-Test Failures and Related Troubleshooting” on page 1-17 and

“Troubleshooting Unlocks” on page 1-68.)

1. Set the signal generator to the unleveled frequency.

2. With the signal generator powered on, carefully remove the A14 Extended Frequency Output.

3. Use a semi-rigid cable extender and connect a sp ectrum analyzer to the A22 Coupler on the coupled output at J4 of the A14 Extended Frequency Output.

The signal at J4 should be the same frequency that the signal generator is set to and the amp litude at J4 should be ≥−8dBm.

• If the J4 signal is good, replace the A14 Extended Frequency Output.

• If the J4 signal is bad, measure the signal at the cable (W54) connected to the input

of the A22 Coupler. — If the signal is good, change the A22 Coupler.

— If the signal is bad, check the signal leaving the YIG Oscillator.

The YIG frequency will be the same as the front panel frequency. — If the signal is good, replace the semi-rigid cable (W54) between the YIG Oscillator and the input of the

A22 Coupler. (Refer to “Semi-Rigid Cables - Includes the A21 YTO Driver and the AT1 High-Power

Mechanical Attenuator (Option UNB) with an A29 DC Blocking Capacitor” on page 2-58.)

— If the signal is bad, change the A21 YTO Driver.

1-77

Troubleshooting

Troubleshooting the AT1 Electronic Attenuator

The AT1 Electronic Attenuator has an attenuation range of 130 dB in 5 dB steps. This attenuator is used to coarse-tune the power level while the Automatic Leveling Control (ALC) loop is u sed to fine -tun e the power level; the ALC fine-tunes the power level within each 5 dB step.

The attenuator is set to 0 dB attenuation for power levels from 0 dBm to +25 dBm. The first 5 dB s tep is switch ed in at approximately −0.5 dBm, the second step is switched in at approximately −5.5 dBm, the third step is switched in at approximately −10.5 dBm; this pattern repeats until the last 5 dB step is switched in at approximately −125.5 dBm. Attenuator control comes from the A23 Motherboard through A23J25.

Table 1-35

Power Supply Voltage (Vdc)

+12 J25-14 +12.10 +12.90 A23 Motherboard

−12 J25-13 −12.90 −12.10 A23 Motherboard +5 J25-15 +4.5 +5.356 Main Supply

❏ Check the power supply voltage on A23J25.

— If the powe r supply volt age on A23J25 is good:

1. Set the amplitude to +0 dBm.

2. Set the amplitude increment to 5 dB.

3. Set the

4. Set the amplitude level using the Down arrow key.

5. Use Table 1-38 to isolate the problem.

RF On/Off to RF On.

— If the attenuator control line voltages are correct for the given amplitude setting,

check the attenuator ribbon cable (W57): — If the attenuator ribbon cable is good, replace the AT1 Electronic Attenuator.

— If the attenuator ribbon cable is bad, replace W57.

— If the attenuator control line voltages are wrong for the given amplitude setting,

check the that the control voltages change within a 5 dB range (Refer to Table 1-38.):

Connector Pins on the A23 Motherboard

Minimum Value (Vdc)

Maximum Value (Vdc)

Origin

— If the attenuator control line voltages change within 5 dB, return the unit back to Agilent Technologies for

calibration.

— If the attenuator control line voltages do not change within 5 dB, replace the A23 Motherboard. (Refer to

“Self-Tests 21xx for the A23 Motherboard” on page 1-62.)

— If the power supply voltage on A23J25 is bad, troubleshoot the A6 Power Supply. (Refer to “Power Supplies” on

page 1-21.)

1-78

Troubleshooting

Troubleshooting the AT1 Electron ic Attenuator

NOTE Table 1-36 shows the amplitude levels and the corresponding attenuator control line voltages. The amplitude

levels are chosen so that they are approximately in the center of each 5 dB switch point. Due to calibration variations, the absolute range of each 5 dB attenuation step may have to be re-established. This can be accomplished by decreasing the power setting while monitoring A23J25 pin 9. Note the power setting when the control line goes TTL-high (+5 V) and continue decreasing the power and noting the power setting when the control line goes TTL low (0 V). The difference in the two settings is the new range. Once a new range is established, use the mid-point of each new range as the amplitude settings in place of the settings in Table

1-36.

Table 1-36 Attenuator Control Lines and Corresponding Amplitude Levels

A23J25 Pin Numbers and Voltages Amplitude Level

(dBm)

+0 0000000

−5 +5000000

−10 +5+500000

−15 +50+50000

−20 +5+5+50000

−25 +50+5+5000

−30 +5 +5 +5 +5 0 0 0

−35 +5 0 +5 0 +5 0 0

−40 +5 +5 +5 0 +5 0 0

−45 +50 +5+5+50 0

−50 +5 +5 +5 +5 +5 0 0

−55 +50+500+50

−60 +5 +5 +5 0 0 +5 0

Pin 4 5dB Step

Pin 9 5dB Step

Pin 6 10 dB Step

Pin 7 10 dB Step

Pin 3 20 dB Step

Pin 5 40 dB Step

Pin 10 40 dB Step

−65 +50 +5+50 +50

−70 +5 +5 +5 +5 0 +5 0

−75 +5 0 +5 0 +5 +5 0

−80 +5 +5 +5 0 +5 +5 0

−85 +50 +5+5+5+50

−90 +5 +5 +5 +5 +5 +5 0

−95 +50+500+5+5

−100 +5+5+50 0 +5+5

1-79

Troubleshooting

Troubleshooting the AT1 Electronic Attenuator

Table 1-36 Attenuator Control Lines and Corresponding Amplitude Levels (Continued)

−105 +5 0 +5 +5 0 +5 +5

−110 +5+5+5+50 +5+5

−115 +50 +50 +5+5+5

−120 +5+5+50 +5+5+5

−125 +5 0 +5 +5 +5 +5 +5

−130 +5+5+5+5+5+5+5

1-80

Troubleshooting

Troubleshooting the AT1 High-Power Mechanical Attenuator

The AT1 High-Power Mechanical Attenuator has an attenuation range of 130 dB in 5 dB steps. This attenuator is used to coarse-tune the power level while the Automatic Lev e ling Control (ALC ) loop is used to fine-tune the power level; the ALC fine-tunes the power level within each 5 dB step.

The attenuator is set to 0 dB attenu ation for power levels from 0 dBm to +25 dBm. The first 5 dB step is switched in at approximately −0.5 dBm, the second step is switched in at approximately −5.5 dBm, the third step is switched in at approximately −10.5 dBm; this pattern repeats until the last 5 dB step is switched in at approximately −125.5 dBm. Attenuator control comes from the A23 Motherboard through A23J25.

Table 1-37

Power Supply Voltage (V dc) Connector Pins on

A23 Motherboard

+15 J25-1 +14.1 +15.9 Main Supply

❏ Check the power supply voltage on A23J25 pin 1.

— If the power supply voltage on A23J25 pin 1 is good:

1. Set the amplitude to +2 dBm.

2. Set the amplitude increment to 5 dB.

3. Set the

4. Set the amplitude level using the Down arrow key.

5. Use Table 1-38 to isolate the problem.

RF On/Off to RF On.

— If the attenuator control line voltages are correct for the given amplitude setting, check the attenuator ribbon

cable (W57): — If the attenuator ribbon cable is good, replace the AT1 High-Power Mechanical Attenuator.

— If the attenuator ribbon cable is bad, replace W57.

— If the attenuator control line voltages are wrong for the given amplitude setting, check the that the control

voltages change within a 5 dB range (Refer to Table 1-38.):

Minimum Value (Vdc) Maximum Value (Vdc) Origin

— If the attenuator control line voltages change within 5 dB, return the unit back to Agilent Technologies for

calibration.

— If the attenuator control line voltages do not change within 5 dB, replace the A23 Motherboard. (Refer to

“Self-Tests 21xx for the A23 Motherboard” on page 1-62.)

— If the power suppl y vo l tage on A23J25 pin 1 is bad, troubleshoot the A6 Power Supply. (Refer to “Power Supplies” on

page 1-21.)

1-81

Troubleshooting

Troubleshooting the AT1 High-Power Mech anical Attenuator

NOTE Table 1-38 shows the amplitude levels and the corresponding attenuator control line voltages. The amplitude

levels are chosen so that they are approximately in the center of each 5 dB switch point. Due to calibration variations, the absolute range of each 5 dB attenuation step may have to be re-established. This can be accomplished by decreasing the power setting while monitoring A23J25 pin 10. Note the power setting when the control line goes TTL-high (+5 V) and continue decreasing the power and noting the power setting when the control line goes TTL low (0 V). The difference in the two settings is the new range. Once a new range is established, use the mid-point of each new range as the amplitude settings in place of the settings in Table

1-38.

Table 1-38 Attenuator Control Lines and Corresponding Amplitude Levels

A23J25 Pin Numbers and Voltages Amplitude Level

(dBm) +2 00000

−3 +50000

−8 0+5000

−13 +5 +5 0 0 0

−18 00+500

−23 +5 0 +5 0 0

−28 0 +5+50 0

−33 +5 +5 +5 0 0

−38 000+50

−43 +500+50

−48 0 +5 0 +5 0

−53 +5 +5 0 +5 0

−58 0000+5

−63 +5000+5

Pin 10 5dB Step

Pin 9 10 dB Step

Pin 6 20 dB Step

Pin 7 40 dB Step

Pin 5 60 dB Step

−68 0+500+5

−73 +5 +5 0 0 +5

−78 00+50+5

−83 +5 0 +5 0 +5

−88 0 +5+50 +5

−93 +5 +5 +5 0 +5

−98 000+5+5

−103 +500+5+5

−108 0 +5 0 +5 +5

1-82

Troubleshooting

Troubleshooting the AT1 High-Power Mechanical Attenuator

Table 1-38 Attenuator Control Lines and Corresponding Amplitude Levels

−113 +5+50 +5+5

−118 0 0 +5+5+5

−123 +5 0 +5 +5 +5

−128 0 +5 +5 +5 +5

1-83

Troubleshooting

Troubleshooting Adjustment Problems

When an adjustment does not work or fails to resolve a p roblem and all self-te sts have passed, us e the fol lowing t able to locate the most likely failure.

NOTE Agilent Technologies recommends calibrating the E4428C/38C ESG-C Signal Generator every two years.

Table 1-39 Troubleshooting Adjustment Problems

The following adjustments are listed in the order that they should be performed for proper calibration.

Adjustment that is failing... Assemblies most likely causing failure...

Analog Bus ADC Calibration

• A12 CPU

• Refer to “Troubleshooting Analog Bus ADC Ca libration Failures” on page1-87

Pretune Calibration (Option UNJ or Option 506 Only)

Internal Source Calibration

VCO Bias Potentiometer Calibration

Lock Angle Potentiometer Calibration (Not Used with Option UNJ or Option 506) KV versus Frequency Calibration

Timebase DAC Calibration FM Scale DAC Offset Calibration FM Path Offset Calibration FM In-Band DAC Offset Calibration

FM Inverting Amplifier Offset Calibration

FM 1/2 Path Ratio Gain Calibration Modulation Source Relative Gain Calibra tion

FM Out-of-Band Calibration (Not Used with Option UNJ or Option 506)

FM/PM YO Frequency Compensation Calibration (Option UNJ or Option 506 Only) DCFM Calibration

• A21 YTO Driver

• A16 Frac-N

• A23 Motherboard

• A18 Reference

• A17 Synthesizer

• A16 Frac-N

• A17 Synthesizer

• A16 Frac-N

• A18 Reference

• A16 Frac-N

• A17 Synthesizer

• A16 Frac-N

• A17 Synthesizer

• A18 Reference

• A23 Motherboard

• A16 Frac-N

• A21 YTO Driver

• A16 Frac-N

Low Frequency (LF) Output Calibration

External Input Peak Detector Calibration

1-84

• A17 Synthesizer

• A18 Reference

• A23 Motherboard

• A18 Reference

Troubleshooting Adjustment Problems

Table 1-39 Troubleshooting Adjustment Problems (Continued)

The following adjustments are listed in the order that they should be performed for proper calibration.

Adjustment that is failing... Assemblies most likely causing failure...

Burst Modulator Calibration

Burst Audio Path Gain Calibration

AM Audio Path Offset Calibration Prelevel Calibration

VBLO Mixer Bias Calibration

Digital Gain Adjust Calibration (E4438C Only)

Bypass Gain Adjust Calibration

• A13 Output

• A14 Extended Fre quency Output

• A13 Output

• A14 Extended Fre quency Output

• A18 Reference

• A13 Output

• A14 Extended Fre quency Output

• A13 Output

• A14 Extended Fre quency Output

• A13 Output

• A14 Extended Fre quency Output

• A13 Output

Troubleshooting

ALC Calibration

Power Level Accuracy, High Power Calibration

ALC Modulation Driver Bias Calibration

• A14 Extended Fre quency Output

• A13 Output

• A14 Extended Fre quency Output

• AT1 High-Power Mech ani cal Attenuator

• A28 Reverse Power Protection

• A13 Output

• A14 Extended Fre quency Output

• A29 DC Blocking Capac it or

• A13 Output

• A14 Extended Fre quency Output

1-85

Troubleshooting

Troubleshooting Adjustment Problems

Table 1-39 Troubleshooting Adjustment Problems (Continued)

The following adjustments are listed in the order that they should be performed for proper calibration.

Adjustment that is failing... Assemblies most likely causing failure...

Power Level Accuracy, Low Power Calibration

Power Search Calibration

AM Gain Calibration

I/Q Gain/Offset/Quadrature Calibration (E4438C Only)

I/Q Impairment Calibration (E4438C Only)

• AT1 High-Power Mech ani cal Attenuator

• A28 Reverse Power Protection

• Loose or leak y R F cables

• A13 Output

• A14 Extended Fre quency Output

• A13 Output

• A14 Extended Fre quency Output

• A10 I/Q Multiplexer

• A13 Output

• A14 Extended Fre quency Output

• A7 Baseband Generator

• A10 I/Q Multiplexer

• A13 Output

• A14 Extended Fre quency Output

1-86

Agilent E4438C Service Guide

Specifications and Main Features

Frequently Asked Questions

User Manual

Documentation Overview

1 Troubleshooting

Before Troubles hooting

ESD Information

Getting Started with Troubleshooting

Troubleshooting Aids

ILT-1 Power Supply Failure and Self-Test

ILT-2 A12 CPU Power-On Test

ILT3 Front Panel Display Troubleshooting

Symptom: If the Display is Dark

Symptom: If the Display is Bright, but without Characters

Symptom: If Hardkeys or Softkeys are Not Functioning

Symptom: If the RPG Knob is Not Functioning

Symptom: If the Screen Saver is Not Functioning

Self-Test Failures and Related Troubleshooting

Overview

Running Self-Test

Troubleshooting Assembly Level Problems

Power Supplies

Self-Tests 1xx for the A10 I/Q Multiplexer (E4438C Only)

Self-Tests 2xx for the A15 Sampler

Self-Tests 4xx for the A13 Output

Self-Tests 5xx for the A17 Synthesizer

Self-Tests 6xx for the A21 YTO Driver

Self-Tests 7xx for the A16 Frac-N

Self-Tests 8xx for the A18 Reference

Self-Tests 11xx for the A12 CPU

Self-Tests 20xx for the A14 Extended Frequency Output

Self-Tests 21xx for the A23 Motherboard

Self-Tests 23xx for the A13 Output

Troubleshooting Unlocks

514 Reference Oven Cold

515 10 MHz Signal Bad

512 Reference Unlocked

513 1 GHz Out of Lock

508 Frac-N Loop Unlock (Option 501, 502, 503, 504)

508 Frac-N Loop Unlock (Option UNJ and Option 506)

520 Sampler Unlocked (Option UNJ and Option 506)

521 YO Loop Unlocked (Option UNJ and Option 506)

516 Baseband Generator Unlock (E4438C Only)

623 Demod Unlock (E4438C Only)

Troubl eshooting Unlevels and th e RF Path

Troubleshooting a Leveling Problem

Troubleshooting the AT1 Electronic Attenuator

Troubleshooting the AT1 High-Power Mechanical Attenuator

Troubleshooting Adjustment Problems