Harris 994 9202 002, 994 9203 002, 994 9204 002, 994 9205 002 Technical Manual

TECHNICAL MANUAL

GATES ONE - 994 9202 002

GATES TWO - 994 9203 002

GATES FIVE (1-PHASE) - 994 9204 002

GATES Series™

AM TRANSMITTERS

GATES FIVE (3-PHASE) - 994 9205 002

T.M. No. 888-2314-001

2000, 2001, 2002

Printed: 1990

Rev. AF: 06-21-02

Returns And Exchanges

Damaged or undamaged equipment should not be returned unless written approval and a Return Authorization is received from HARRIS CORPORATION, Broadcast Systems Division. Special shipping instructions and coding will be provided to assure proper handling. Complete details regarding circumstances and reasons for return are to be included in the request for return. Custom equipment or special order equipment is not returnable. In those instances where return or exchange of equipment is at the request of the customer, or convenience of the customer, a res tocking fee will be charged. All returns will be sent freight prepaid and properly insured by the customer. When communicating with HARRIS CORPORATION, Broadcast Systems Div ision, specify the HARRIS Order Number or Invoice Number.

Unpacking

Carefully unpack the equipment and preform a visual inspection to determine that no apparent damage was incurred during shipment. Retain the shipping materials until it has been determined that all received equipment is not damaged. Locate and retain all PACKING CHECK LISTs. Use the PACKING CHECK LIST to help locate and identify any components or assemblies which are removed for shipping and must be reinstalled. Also remove any shipping supports, straps, and packing materials prior to initial turn on.

Technical Assistance

HARRIS Technical and Troubleshooting assistance is available from HARRIS Field Service during normal business hours (8:00 AM - 5:00 PM Central Time). Emergency service is available 24 hours a day. Telephone 217/222-8200 to contact the Field Service Department or address correspondence to Field Service Department, HARRIS CORPORATION, Broadcast Systems Division, P.O. Box 4290, Quincy, Illinois 62305-4290, USA. Technical Support by e-mail: tsupport@harris.com. The HARRIS factory may also be contacted through a FAX facility (217/221-7096).

Replaceable Parts Service

Replacement parts are available 24 hours a day, seven days a week from the HARRIS Service Parts Department. Telephone 217/222-8200 to contact the service parts department or address correspondence to Service Parts Department, HARRIS CORPORATION, Broadcast Systems Division, P.O. Box 4290, Quincy, Illinois 62305-4290, USA. The HARRIS factory may also be contacted through a FAX facility (217/221-7096).

NOTE

The # symbol used in the parts list means used with (e.g. #C001 = used with C001).

MANUAL REVISION HISTORY

GATES Series™ AM Transmitters

888-2314-xxx

Rev. A April 1990 None Replaced the following pages: Title Page, v, vii, 2-1 thru 2-6, 3-3, 3-4, 4-3, 4-4, 5-1 thru 5-6, J-3, & J-4

B Aug. 1990 None Replaced the following pages: Title Page, v, 3-5, 3-6, 4-1 thru 4-4, A-1, B-1, B-2, C-2, E-3, F-1 thru F-3,

C Aug. 1990 35969 Replaced the following pages: Title Page, MRH-1/MRH-2, C-4, & C-5 D Aug. 1990 Field

E Sept. 1990 36322 Replace the following pages: Title Page, MRH-1/MRH-2, & all of Section VI F Oct. 1990 36415 Replace the following pages: Title Page, MRH-1/MRH-2, & all of Section A G Jan. 1991 Errata

H June 1991 FS

I July 1991 36962 Replace the following pages: Title Page, MRH-1/MRH-2, and K-3 J Aug. 1991 36963 Replace the following pages: Title Page, MRH-1/MRH-2, 6-9 to 6-12, & J-9 TO J-11 K Jan. 1992 37611 &

L June 1992 37442 Replaced Title Page, MRH-1/MRH-2 and pages 6-14 to 6-17 M Jan. 1994 38809 Replaced Title Page, MRH-1/MRH-2, page K-3, and all of section VI N Feb. 1994 38895 Replaced Title Page, MRH-1/MRH-2, and pages F-4 & F-5 P July 1994 39302 Replaced Title Page, MRH-1/MRH-2, and all of section VI R Dec. 1994 39223 Replaced Title Page, MRH-1/MRH-2, and pages F-4 & F-5 S July 1995 39125 Replaced Title Page, MRH-1/MRH-2, and all of section VI T Jan. 1996 41051R Replaced Title Page, MRH-1/MRH-2, Table of Contents, 1-2 to 1-4, all of sections 2, 4, & 5 U Jan. 1996 41051R Replaced Tit le Page, MRH-1/MRH-2, and pages 6-15 to 6-19 V Mar. 1996 TBD Replaced Title Page, MRH-1/MRH-2, and page 2-9 X Dec. 1996 41575 Replaced Title Page, MRH-1/MRH-2, iv thru vi, and all of Section C Y May 1998 42198 Replaced Title Page, MRH-1/MRH-2, and page 2-4 Y1 10-02-98 42359 Replaced Title Page, MRH-1/MRH-2, page G-6 and all of Section VI Z 12-22-98 38895A Replaced Title Page, MRH-1/MRH-2, and all of Section F Z1 2-15-99 42544 Replaced Title Page, MRH-1/MRH-2, and pages C-4 & C-5. Z2 2-25-99 42636 Replaced Title Page, MRH-1/MRH-2, and all of Section VI AA 08-18-99 45024 Replaced Title Page, MRH-1/MRH-2, and all of Section H AB 12-10-99 45544 Replaced Title Page, MRH-1/MRH-2 and pages 2-4 and 2-5 AC 02-20-00 45748 Replaced Title Page, MRH-1/MRH-2 and all of Section II AD 10-04-01 47730 Replaced Title Page, MRH-1/MRH-2 and page 3-6 AD1 01-15-02 47924 Replaced Title Page, MRH-1/MRH-2, and all of Section VI AE 03-05-02 48100 Replace Title Page, MRH1/MRH2, all parts lists and chapter B. AF 06-21-02 48426 Replace Title Page, MRH1/MRH2, and page C-3

Date ECN

Service Request

FS Request

Request

Misc

Pages Affected

Added MRH-1/MRH-2

G-1 thru G-4, J-1, J-2, J-3, J-4, J-9 thru J-11, & K-3

Replace the following pages: Title Page, MRH-1/MRH-2, & 2-5

Replace the following pages: Title Page, MRH-1/MRH-2, & all of Section VI

Replace the following pages: Title Page, MRH-1/MRH-2, 2-6, G-2, & J-3

Replaced Title Page, MRH-1/MRH-2 and all part lists in manual

888-2314-001 MRH-1/MRH-2

Guide to Using Harris Parts List Information

The Harris Replaceable Parts List Index portrays a tree structure with the major items being leftmost in the index. The example below shows the Transmitter as the highest item in the tree structure. If you were to look at the bill of materials table for the Transmitter you would find the Control Cabinet, the PA Cabinet, and the Output Cabinet. In the Replaceable Parts List Index the Control Cabinet, PA Cabinet, and Output Cabinet show up one indentation level below the Transmitter and implies that they are used in the Transmitter. The Controller Board is indented one level below the Control Cabinet so it will show up in the bill of material for the Control Cabinet. The tree structure of this same index is shown to the right of the table and shows indentation level versus tree structure level.

Example of Replaceable Parts List Index and equivalent tree structure:

The part number of the item is shown to the right of the description as is the page in the manual where the bill for that part number starts.

Inside the actual tables, four main headings are used:

Table #-#. ITEM NAME - HARRIS PART NUMBER -this line gives the information that corresponds to the Replaceable Parts List Index entry;

HARRIS P/N column gives the ten digit Harris part number (usually in ascending order); DESCRIPTION column gives a 25 character or less description of the part number; REF. SYMBOLS/EXPLANATIONS column 1) gives the reference designators for the item (i.e., C001, R102, etc.) that

corresponds to the number found in the schematics (C001 in a bill of material is equivalent to C1 on the schematic) or

2) gives added information or further explanation (i.e., “Used for 208V operation only,” or “Used for HT 10LS only,” etc.).

Inside the individual tables some standard conventions are used:

A # symbol in front of a component such as #C001 under the REF. SYMBOLS/EXPLANATIONS column means that this item is used on or with C001 and is not the actual part number for C001.

In the ten digit part numbers, if the last three numbers are 000, the item is a part that Harris has purchased and has not manufactured or modified. If the last three numbers are other than 000, the item is either manufactured by Harris or is purchased from a vendor and modified for use in the Harris product.

The first three digits of the ten digit part number tell which family the part number belongs to - for example, all electrolytic (can) capacitors will be in the same family have a 9xx xxxx xxx part number (a number outside of the normal family of numbers), it has probably been modified in some manner at the Harris factory and will therefore show up farther down into the individual parts list (because each table is normally sorted in ascending order). Most Harris made or modified assemblies will have 9xx xxxx xxx numbers associated with them.

The term “SEE HIGHER LEVEL BILL” in the description column implies that the reference designated part number will show up in a bill that is higher in the tree structure. This is often the case for components that may be frequency determinant or voltage determinant and are called out in a higher level bill structure that is more customer dependent than the bill at a lower level.

(524 xxxx 000). If an electrolytic (can) capacitor is found to

Rev. X 888-2314-001 iii

WARNING: Disconnect primary power prior to servicing.

iv 888-2314-001 Rev. X

WARNING: Disconnect primary power prior to servicing.

WARNING

THE CURRENTS AND VOLTAGES IN THIS EQUIPMENT ARE DANGEROUS. PERSONNEL MUST AT ALL TIMES OBSERVE SAFETY WARNINGS, INSTRUCTIONS AND REGULATIONS.

This manual is intended as a general guide for trained and qualified personnel who are aware of the dangers inherent in handling potentially hazardous electrical/electronic circuits. It is not intended to contain a complete statement of all safety precautions which should be observed by personnel in using this or other electronic equipment.

The installation, operation, maintenance and service of this equipment involves risks both to personnel and equipment, and must be performed only by qualified personnel exercising due care. HARRIS CORPORATION shall not be responsible for injury or damage resulting from improper procedures or from the use of improperly trained or inexperienced personnel performing such tasks.

During installation and operation of this equipment, local building codes and fire protection standards must be observed. The following National Fire Protection Association (NFPA) standards are recommended as reference:

- Automatic Fire Detectors, No. 72E

- Installation, Maintenance, and Use of Portable Fire Extinguishers, No. 10

- Halogenated Fire Extinguishing Agent Systems, No. 12A

WARNING

ALWAYS DISCONNECT POWER BEFORE OPENING COVERS, DOORS, ENCLOSURES, GATES, PANELS OR SHIELDS. ALWAYS USE GROUNDING STICKS AND SHORT OUT HIGH VOLTAGE POINTS BEFORE SERVICING. NEVER MAKE INTERNAL ADJUSTMENTS, PERFORM MAINTENANCE OR SERVICE WHEN ALONE OR WHEN FATIGUED.

Do not remove, short-circuit or tamper with interlock switches on access covers, doors, enclosures, gates, panels or shields. Keep away from live circuits, know your equipment and don’t take chances.

WARNING

IN CASE OF EMERGENCY ENSURE THAT POWER HAS BEEN DISCONNECTED.

WARNING

IF OIL FILLED OR ELECTROLYTIC CAPACITORS ARE UTILIZED IN YOUR EQUIPMENT, AND IF A LEAK OR BULGE IS APPARENT ON THE CAPACITOR CASE WHEN THE UNIT IS OPENED FOR SERVICE OR MAINTENANCE, ALLOW THE UNIT TO COOL DOWN BEFORE ATTEMPTING TO REMOVE THE DEFECTIVE CAPACITOR. DO NOT ATTEMPT TO SERVICE A DEFECTIVE CAPACITOR WHILE IT IS HOT DUE TO THE POSSIBILITY OF A CASE RUPTURE AND SUBSEQUENT INJURY.

Rev. X 888-2314-001 v

WARNING: Disconnect primary power prior to servicing.

vi 888-2314-001 Rev. X

WARNING: Disconnect primary power prior to servicing.

FIRST-AID

Personnel engaged in the installation, operation, maintenance or servicing of this equipment are urged to become familiar with first-aid theory and practices. The following information is not intended to be complete first-aid procedures, it is a brief and is only to be used as a reference. It is the duty of all personnel using the equipment to be prepared to give adequate Emergency First Aid and thereby prevent avoidable loss of life.

Treatment of Electrical Burns

1. Extensive burned and broken skin a. Cover area with clean sheet or cloth. (Cleanest available cloth article.)

b. Do not break blisters, remove tissue, remove adhered particles of clothing, or apply any salve or ointment.

c. Treat victim for shock as required.

d. Arrange transportation to a hospital as quickly as possible.

e. If arms or legs are affected keep them elevated.

NOTE

If medical help will not be available within an hour and the victim is conscious and not vomiting, give him a weak solution of salt and soda: 1 level teaspoonful of salt and 1/2 level teaspoonful of baking soda to each quart of water (neither hot or cold). Allow victim to sip slowly about 4 ounces (a half of glass) over a period of 15 minutes. Discontinue fluid if vomiting occurs. (Do not give alcohol.)

REFERENCE:

2. Less severe burns - (1st & 2nd degree) a. Apply cool (not ice cold) compresses using the cleanest available cloth article.

b. Do not break blisters, remove tissue, remove adhered particles of clothing, or apply salve or ointment.

c. Apply clean dry dressing if necessary.

d. Treat victim for shock as required.

e. Arrange transportation to a hospital as quickly as possible.

f. If arms or legs are affected keep them elevated.

ILLINOIS HEART ASSOCIATION

AMERICAN RED CROSS STANDARD FIRST AID AND PERSONAL SAFETY MANUAL (SECOND EDITION)

Rev. X 888-2314-001 vii

WARNING: Disconnect primary power prior to servicing.

TABLE OF CONTENTS

SECTION I

GENERAL INFORMATION

Introduction......................................1-1

ScopeAndPurpose..............................1-1

Specifications....................................1-1

SECTION II

INSTALLATION/OPERATION

Introduction......................................2-1

Unpacking.......................................2-1

ReturnsandExchanges.............................2-1

GeneralInstallationInformation .....................2-1

Power Distribution for Optimum Transmitter Perform-

ance .........................................2-1

OverheatingfromLineUnbalance..............2-1

TransmitterNoisePerformance ................2-1

TheCausesofLineUnbalance.................2-1

ThreePhaseDeltaDistributionTransformers..... 2-2

ThreePhaseWyeDistributionTransformers...... 2-2

General Installation

Requirements ...................................2-2

EquipmentPlacement............................2-2

Pre-InstallationInspection ........................2-2

EquipmentPositioning...........................2-3

Ground Strap Installation ......................... 2-3

ElectricalInstallation ..............................2-3

PowerRequirements.............................2-3

Procedure. .................................2-3

RFOutputConnection........................... 2-4

BatteryInstallation.............................. 2-4

Audio Input .................................... 2-4

RemoteControl.................................2-4

AirflowSensorStatus............................ 2-5

FailsafeConnection..............................2-5

Modulation Monitor Sample ......................2-5

InitialTurnOnProcedure...........................2-5

InitialTurnOn .................................2-5

Modulation Monitor Carrier Level.................. 2-6

ApplicationofAudio ............................2-7

RemoteMeterCalibration ........................2-7

SECTION III

MAINTENANCE

Introduction......................................3-1

StationRecords...................................3-1

Maintenance Logbook ........................... 3-1

PreventiveMaintenance............................3-1

Maintenance Of Components ...................... 3-1

AirSystem.....................................3-2

GATES Series™ Top Removal

Procedure ....................................3-2

LowVoltageSupplyAdjustment...................3-2

High Voltage Supply Adjustment ..................3-4

RFDriveMeasurement........................... 3-4

IPATuning.................................... 3-5

PAVoltageElectricalZero ....................... 3-5

PAVoltMeterCalibration........................3-5

PACurrentCalibration........................... 3-5

Power Supply Current Calibration .................. 3-5

viii 888-2314-001 Rev. X

WARNING: Disconnect primary power prior to servicing.

PowerOutputCalibration........................ 3-5

OverloadAdjustmentProcedures.................. 3-6

Power Supply Current Overload ............... 3-6

UnderdriveFault............................ 3-6

VSWRDetector............................ 3-6

Replacing Boards and

ReplacingBoardComponents ..................... 3-6

SECTION IV

TROUBLESHOOTING

Introduction ..................................... 4-1

Definition of

FrontPanelIndicators ............................ 4-1

Symptom: Transmitter Will Not Turn On - None of

the Green LED’s on the Power Level Switches are Il-

luminated....................................... 4-1

PossibleCauses................................ 4-1

LossofACPower .......................... 4-1

ControlSupplyFailure....................... 4-1

Symptom: Green Power Level Status LED’s Illumi-

nate, but the Primary Contactors Do Not Energize and

NoOverloadLED’sIlluminate..................... 4-1

PossibleCauses................................ 4-1

Phase Monitor (3∅ FIVEonly)................ 4-1

Blownfuse................................ 4-1

OpenInterlock............................. 4-1

FailsafeInterlockOpen ...................... 4-1

InterfaceboardOutput....................... 4-1

OpenContactorCircuit ...................... 4-1

ContactorControlSignal..................... 4-1

Symptom: One or Both Primary Contactors Energize,

ButThereIsNoPowerOutput ..................... 4-1

HighVoltageSupplyFailure...................... 4-1

Symptom: High Voltage Is Present, But There Is No

PowerOutput ................................... 4-2

PDMKillCondition ............................ 4-2

PDMLevel.................................... 4-2

PossibleCausesForOverloads...................... 4-2

Supply Voltage Overload ........................ 4-2

Supply Voltage Too High .................... 4-2

Power Supply Current Overloads- At Turn On ....... 4-2

Supply Short ............................... 4-2

Power Supply Current Overloads, Continuous Cycling

andAutomaticCutback......................... 4-2

PDMSystemProblem....................... 4-2

PDMGeneratorOutputsHigh................. 4-2

PDMAmplifierShorts....................... 4-2

Supply Current Calibration ................... 4-2

Random Supply Current Overloads With Modulation. . 4-2

Sub-audibleSignals......................... 4-2

UnderdriveFault ............................... 4-2

Low/NoDrive.............................. 4-2

IPAandPATransistors...................... 4-2

VSWR Overload- Continuous VSWR Cycling ....... 4-2

BadLoadImpedance........................ 4-2

AntennaProblem........................... 4-3

OutputNetwork............................ 4-3

VSWR Trips With High Levels Of Modulation and

HighPower................................... 4-3

ImproperTuningandLoading................. 4-3

Antenna .................................. 4-3

OutputNetwork............................ 4-3

Symptom:RemoteControlFunctionsDoNotWork .... 4-3

PossibleCauses................................ 4-3

Remote/LocalSwitch........................ 4-3

RemoteControlImproperlyWired............. 4-3

RemoteControlUnitNotFunctioning.......... 4-3

RibbonConnectorsLoose.................... 4-3

CausesforaPAVolts/PAAmpsRatioChange ........ 4-3

No+20VoltstoPDMAmplifier.................. 4-3

ImpedanceChange ............................. 4-3

PAFailure.................................... 4-3

Troubleshooting AM Noise......................... 4-4

50/60Hz...................................... 4-4

AudioLinesareNormallyBalanced ............... 4-4

100/120Hz.................................... 4-4

300/360Hz.................................... 4-4

60kHz....................................... 4-4

RFINoiseonAudio ............................ 4-4

SECTION V

TRANSMITTER OVERALL

Introduction..................................... 5-1

Personnel Protection .............................. 5-1

PrinciplesOfOperation............................ 5-1

FET’SintheGATESSeries™.................... 5-1

PDMTheoryInBrief ........................... 5-1

PolyphaseTheory .............................. 5-1

Audio/PDMSignalFlow......................... 5-1

PDMLoop.................................... 5-3

RFPowerFlow................................ 5-3

Failsafe....................................... 5-3

ACPowerFlow................................ 5-3

High Voltage Power Supply ...................... 5-3

Introduction ............................... 5-3

Description................................ 5-3

Low Voltage Power Supply and IPA Power Supply. . . 5-6

Introduction ............................... 5-6

Description................................ 5-6

AirflowSensor................................. 5-6

Introduction ............................... 5-6

Description................................ 5-6

Section VI

Parts List

Introduction..................................... 6-1

SECTION A

OSCILLATOR (A16)

PrinciplesOfOperation............................ A-1

Replacement/Alignment ........................... A-1

FrequencyAdjustment........................... A-1

Troubleshooting the

RFOscillator ................................... A-1

Symptom:NoOutput ........................... A-1

OpenFuse/Lossof+20V..................... A-1

RFKILL.................................. A-1

Q1,Q2,CR1................................ A-1

U1,CR4...................................A-1

U2.......................................A-1

U3.......................................A-1

SECTION B

IPA (A5)

PrinciplesofOperation.............................B-1

IPATuningNetwork............................B-1

Replacement/Alignment............................B-1

IPA Tuning and Testing

Procedure......................................B-1

IPATuning................................B-1

OhmmeterTestingtheIPA .......................B-1

HandlingMOSFET’s..............................B-1

TestingMOSFET’s ...............................B-2

SECTION C

POWER AMPLIFIER A1 through A4

PrinciplesofOperation.............................C-1

PAToroids......................................C-1

Replacing a PA Module............................C-1

TroubleshootingthePABoards......................C-1

OhmmeterTesting..............................C-1

HandlingMOSFET’s..............................C-2

TestingMOSFET’s ...............................C-2

ReplacingPATransistors.........................C-2

ScopingtheRFDrive..............................C-2

RFDrivePhasingMeasurement .....................C-2

SECTION D

OUTPUT NETWORK

PrinciplesofOperation.............................D-1

AdjustmentProcedures.............................D-1

TuningAndLoadingControls.....................D-1

OutputNetworkColdTuning .....................D-1

ThirdHarmonicTrapL7-C4 ..................D-1

Bandpass Filter L2-C2 .......................D-1

TEENetwork-LoadandTune................D-1

L2SlidingTap .............................D-1

L1Tap....................................D-2

SECTION E

OUTPUT MONITOR (A18)

PrinciplesofOperation.............................E-1

Replacement/Alignment............................E-1

Troubleshooting..................................E-1

Symptom: Detector Null Reading Is High and Cannot

BeAdjustedToZero............................E-1

BadLoadImpedance ........................E-1

SampleSignalMissing.......................E-1

SECTION F

PDM GENERATOR (A15)

PrinciplesOfOperation............................ F-1

Replacement/Alignment............................F-1

TroubleshootingPDMGenerator..................... F-1

Symptom: No Pulses At J4, Causing Zero Power Out-

putfromtheTransmitter......................... F-1

PowerSetting ..............................F-1

LossofPlusandMinus15Volts............... F-1

PDMInterrupt.............................. F-1

DC/AudioFailure........................... F-1

Rev. X 888-2314-001 ix

WARNING: Disconnect primary power prior to servicing.

Symptom:ImbalanceInOutputPulseWidths ........F-2

AudioImbalance............................F-2

TriangleWaveImbalance.....................F-2

Symptom: Output(s) At J2 Always In A High State,

Causing One or More Pdm Amplifiers to Conduct

FullTime.....................................F-2

Symptom:OnlyOneOutputHigh..................F-3

Symptom:TwoOutputsAreHigh..................F-3

Symptom:AllFourOutputsAreHigh ..............F-3

SECTION G

PDM AMPLIFIER/PULL-UP (A6-A9)

PrinciplesofOperation............................ G-1

PDMAmplifier................................ G-1

PDMPull-UpBoard............................ G-1

Maintenance .................................... G-1

PDMAmplifiers............................... G-1

GateDriveChecks............................. G-1

In-Circuit Ohmmetering the PDM Amp Module (A6

thruA9)MOSFET’s........................... G-2

CheckingGateDrive........................ G-4

HandlingMOSFET’s............................. G-4

TestingMOSFET’s............................... G-4

SECTION H

PDM FILTER (A10 and A11)

PrinciplesofOperation............................ H-1

SECTION J

CONTROLLER BOARD (A12)

PrinciplesofOperation............................. J-1

CoarsePowerLevelControl ...................... J-1

ContactorControl............................... J-1

FinePowerControl.............................. J-1

Metering ...................................... J-1

OverloadCircuitry .............................. J-1

OtherFaultDetection............................ J-2

ControllerSupplyVoltages........................J-2

Replacement/AlignmentProcedures...................J-2

PAVoltageElectricalZero........................J-2

PAVoltMeterCalibration ........................J-2

Power Supply Current Calibration ..................J-2

PowerOutputCalibration.........................J-3

OverloadAdjustmentProcedures.....................J-3

Power Supply Current Overload ....................J-3

UnderdriveFault ................................J-3

VSWRDetector.................................J-3

Troubleshooting the Controller .......................J-3

Symptom: Will Not Respond To An On Command ....J-3

Controller Supply Failure ......................J-3

Failedflipflopcircuitry.......................J-3

Symptom: PDM Power Level Signal Cannot Be Con-

trolled ........................................J-3

Symptom:MultimeterIsPinnedFarLeftorRight .....J-3

Symptom: Some Remote Control Functions Do Not

Work.........................................J-3

SECTION K

INTERFACE BOARD (A24)

PrinciplesofOperation............................ K-1

Replacement/Alignment............................ K-1

Troubleshooting .................................. K-1

Symptom: Green Power Level Status LED’s Light On

Controller,ButTheContactorsDoNotEnergize.....K-1

OpenInterlock............................. K-1

24VACMissing............................ K-1

ONCommandMissing ...................... K-1

BadTriacorOpticalIsolator..................K-1

APPENDIX L

TEST EQUIPMENT

Introduction ..................................... L-1

x 888-2314-001 Rev. X

WARNING: Disconnect primary power prior to servicing.

SECTION I

GENERAL INFORMATION

1.1. Introduction

1.1.1. Scope And Purpose

This technical manual contains the information necessary to install and maintainthe GATES Series™ AM Transmitters. The various sections of this technical manual provide the following types of information.

Section I, General Information, provides introduction to technical manual contents. Section II, Installation/operation, provides detailed installation and operation procedures. Section III, Maintenance, provides preventive and corrective maintenance as well as tuning procedures (alignment procedures).

Section IV, Troubleshooting, provides a listing of the protection devices in the transmitter as well as troubleshooting procedures. Section V, Transmitter Overall, provides theory of operation of the various sections of the transmitter not covered in later sections. Section VI, Parts List, provides parts list for the transmitter.

The following sections provideprinciples of operation, maintenance information, troubleshooting,and parts lists forboardsin GATES Series™ transmitter:

Section A, Oscillator Section B, IPA Section C, Power Amplifier Section D, Output Network

Section E, Output Monitor Section F, PDM Generator Section G, PDM Amplifier/Pull-Up Section H, PDM Filter Section J, Controller Section K, Interface Board Appendix L, Test Equipment, provides a list of the test equipment provided and recommended to perform maintenance on the transmitter.

1.2. Specifications

Table 1-1, 1-2, and 1-3 list the specifica-

tions of the GATES Series™ transmitters.

NOTE

Specifications subject to change without notice.

Rev. T: Jan. 1996 888-2314-001 1-1

WARNING: Disconnect primary power prior to servicing.

Table 1-1. GATES ONE Specifications

POWER OUTPUT: 1000 watts (Rated). Six power levels adjustable between 100-1100 watts. Capable

of lower power PSA/PSSA operation. RF FREQUENCY RANGE: 531 kHz through 1705 kHz. Supplied to one frequency as ordered. CARRIER FREQUENCY STABILITY: Crystal control oscillator meets FCC specifications. +/-4 Hz in typical operating

environment. RF OUTPUT IMPEDANCE: 50 ohms unbalanced. RF OUTPUT TUNING: Integral network will match a VSWR of 1.5:1 to 1.0:1 at carrier. RF OUTPUT TERMINAL: Type N female connector. CARRIER SHIFT: Less than 1% at 100% modulation at 1000 Hz. RF HARMONICS AND SPURIOUS EMISSIONS: Exceeds FCC and CCIR specifications. OTHER EMISSIONS: Meets FCC NRSC 2 when presented with audio signal conforming to NRSC 1

standard. TYPE OF MODULATOR: Patented Polyphase PDM. AUDIO FREQUENCY RESPONSE: +/-0.5 dB, from 20 to 10,000 Hz (with Bessel filter out). AUDIO HARMONIC DISTORTION: Less than 1.0% at 1 kW, 20 to 10,000 Hz @ 95% modulation. AUDIO INTERMODULATION DISTORTION: Less than 1.0%, 60/7000 Hz 1:1. Less than 1.5%, 60/7000 Hz 4:1, SMPTE

standards at 1 kW operation at 95% modulation. SQUAREWAVE OVERSHOOT: Less than 3.5% at 400 Hz. SQUAREWAVE TILT: Less than 3% at 20 Hz, 90% modulation.

Less than 1.5% at 40 Hz, 90% modulation. NOISE (UNWEIGHTED) Better t han 60 dB below 100% modulation, 1000 Hz at 1kW. POSITIVE PEAK CAPABILITY: Greater than 130% positive peak program modulation capability at 1100 watts. INCIDENTAL QUADRATURE MODULATION

30 dB typical below 95% modulation of L+R channel at 1 kHz. (IQM):

AUDIO INPUT: Continuously adjustable from -10 to +10 dBm, transformer-less active 600 ohms

input. ACVOLTAGE INPUT: 197-251 VAC, 50/60 Hz, single phase. OVERALL EFFICIENCY: Better than 65% at 1000W. POWER CONSUMPTION: At 1000 watts carrier, 1538 watts or less at 0% modulation, 2307 watts or less at

100% sine wave modulation, 1923 watts during typical programming. MONITOR PROVISIONS: Adjustable to 5 volts nominal RMS modulated output sample at 50 ohms for six

power levels from 100 watts to 1100 watts. REMOTE CONTROL/MONITORING: Self-contained interface for most remote control systems TTL compatible. AMBIENT TEMPERATURERANGE: -10°Cto+50°C AMSL (derate upper limit 2°C per 1000 feet altitude). AMBIENT HUMIDITY RANGE: To 95%, non condensing. AIR FLOW: 500 CFM HEAT GENERATED: 2756 BTU per hour at 1 KW 100% tone modulation. ALTITUDE: Up to 13,000 feet (4000 meters). SIZE: 72"H X 28"W X 30"D (1830mm X 712 mm X 762 mm). WEIGHT: (Unpacked) 400 lbs. (181 kg) - approximate. Domestic packed, 600 lbs. (275 kg)

- approximate. Export packed, 700 lbs. (320 kg) - approximate. CUBAGE: 68.7 cubic feet (2 cubic meters) packed. NOTE: ALL SPECIFICATIONS TAKEN WITH TRANSMITTER CONNECTED TO TEST LOAD. SPECIFICATIONS SUBJECT

TO CHANGE WITHOUT NOTICE.

1-2 888-2314-001 Rev. T: Jan. 1996

WARNING: Disconnect primary power prior to servicing.

Table 1-2. GATES TWO Specifications

POWER OUTPUT: 2500 watts (Rated). Six power levels adjustable between 250-2750 watts. Capable of

lower power PSA/PSSA operation. RF FREQUENCY RANGE: 531 kHz through 1705 kHz. Supplied to one frequency as ordered. CARRIER FREQUENCY STABILITY: Crystal control oscillator meets FCC specifications. +/-4 Hz in typical operating

environment. RF OUTPUT IMPEDANCE: 50 ohms unbalanced. RF OUTPUT TUNING: Integral network will match a VSWR of 1.5:1 to 1.0:1 at carrier. RF OUTPUT TERMINAL: 7/8" EIA male/female flange connector. CARRIER SHIFT: Less than 1% at 100% modulation at 1000 Hz. RF HARMONICS AND SPURIOUS EMIS-

Exceeds FCC and CCIR specifications. SIONS:

OTHER EMISSIONS: MeetsFCCNRSC2whenpresentedwithaudiosignalconformingtoNRSC1standard. TYPE OF MODULATOR: Patented Polyphase PDM. AUDIO FREQUENCY RESPONSE: +/-0.5 dB, from 20 to 10,000 Hz (with Bessel filter out). AUDIO HARMONIC DISTORTION: Less than 1.0% at 2500 watts, 20 to 10,000 Hz @ 95% modulation. AUDIO INTERMODULATION DISTORTION: Less than 1.0%, 60/7000 Hz 1:1. Less than 1.5%, 60/7000 Hz 4:1, SMPTE standards

at 2500 watts operation at 95% modulation. SQUAREWAVE OVERSHOOT: Less than 3.5% at 400 Hz. SQUAREWAVE TILT: Less than 3% at 20 Hz, 90% modulation.

Less than 1.5% at 40 Hz, 90% modulation. NOISE (UNWEIGHTED): Better than 60 dB below 100% modulation, 1000 Hz at 2500 watts. POSITIVE PEAK CAPABILITY: Greater than 130% positive peak program modulation capability at 2750 watts. INCIDENTAL QUADRATURE MODULA-

30 dB typical below 95% modulation of L+R channel at 1 kHz. TION (IQM):

AUDIOINPUT: Continuouslyadjustablefrom-10to+10dBm,transformer-lessactive600ohmsinput. AC VOLTAGE INPUT: 197-251 VAC, 50/60 Hz, single phase. OVERALL EFFICIENCY: Better than 65% at 2500W. POWER CONSUMPTION: At 2500 watts carrier,3846 watts or less at 0%modulation, 5769 watts or less at 100%

sine wave modulation, 4807 watts during typical programming. MONITOR PROVISIONS: Adjustable to5 volts nominal RMSmodulated output sample at50 ohms for sixpower

levels from 250 watts to 2750 watts. REMOTE CONTROL/MONITORING: Self-contained interface for most remote control systems TTL compatible. AMBIENT TEMPERATURERANGE: -10°Cto+50°C AMSL (derate upper limit 2°C per 1000 feet altitude). AMBIENT HUMIDITY RANGE: To 95%, non condensing. AIR FLOW: 500 CFM HEAT GENERATED: 6895 BTU per hour at 2500 watts, 100% tone modulation. ALTITUDE: Up to 13,000 feet (4000 meters). SIZE: 72"H X 28"W X 30"D (1830 mm X 712 mm X 762 mm). WEIGHT: (Unpacked) 450 lbs. (204 kg) - approximate. Domestic packed, 650 lbs. (298 kg) -

approximate. Export packed, 750 lbs. (343 kg) - approximate. CUBAGE: 68.7 cubic feet (2 cubic meters) packed. NOTE: ALL SPECIFICATIONS TAKEN WITH TRANSMITTER CONNECTED TO TEST LOAD. S PECIFICATIONS SUBJECT

TO CHANGE WITHOUT NOTICE.

Rev. T: Jan. 1996 888-2314-001 1-3

WARNING: Disconnect primary power prior to servicing.

Table 1-3. GATES FIVE Specifications

POWER OUTPUT: 5000 watts (Rated). Six power levels adjustable between 500-5600 watts. Capable of

Exceeds FCC and CCIR specifications. SIONS:

OTHER EMISSIONS: Meets FCC NRSC 2 when presented with audio signal c onforming to NRSC 1

standard. TYPE OF MODULATOR: Patented Polyphase PDM. AUDIO FREQUENCY RESPONSE: +/-0.5 dB, from 20 to 10,000 Hz (with Bessel filter out). AUDIOHARMONIC DISTORTION: Less than 0.8% at 5000 watts, typically less than 1.5% at 1 kW, 20 to 10,000 Hz @

95% modulation. AUDIO INTERMODULATION DISTORTION: Less than 1.0%, 60/7000 Hz 1:1. Less than 1.5%, 60/7000 Hz 4:1, SMPTE standards

at 5000 watts operation at 95% modulation. SQUAREWAVE OVERSHOOT: Less than 3.5% at 400 Hz. SQUAREWAVE TILT: Less than 3% at 20 Hz, 90% modulation.

Less than 1.5% at 40 Hz, 90% modulation. NOISE (UNWEIGHTED): Better than 60 dB below 100% modulation, 1000 Hz at 2500 watts to 5000 watts. POSITIVE PEAK CAPABILITY: Greater than 130% positive peak program modulation capability at 5600 watts. INCIDENTAL QUADRATURE MODULA-

30 dB typical below 95% modulation of L+R channel at 1 kHz. TION (IQM):

AUDIO INPUT: Continuouslyadjustable from -10 to+10dBm,transformer-lessactive600 ohms input. ACVOLTAGE INPUT: 197-251 VAC, 50/60 Hz, three phase or international 341 to 434 VAC. Compatible

with WYE or closed delta power sources. AC voltage variation: +5, -10% for full

performance. Single phase version accepts 197 to 251 VAC 50/60 Hz. OVERALL EFFICIENCY: Better than 65% at 5000W. POWER CONSUMPTION: At 5000 watts carrier, 7692 watts or less at 0% modulation, 11538 watts or less at

100% sine wave modulation, 9615 watts during typical programming. MONITOR PROVISIONS: Adjustableto 5 volts nominal RMS modulated output sample at50ohms for six power

levels from 500 watts to 5600 watts. REMOTE CONTROL/MONITORING: Self-contained interface for most remote control systems TTL compatible. AMBIENT TEMPERATURERANGE: -10°Cto+50°C AMSL (derate upper limit 2°C per 1000 feet altitude). AMBIENT HUMIDITY RANGE: To 95%, non condensing. AIR FLOW: 500 CFM, (14.16 CMM). HEAT GENERATED: 13790 BTU per hour at 5000 watts, 100% tone modulation. ALTITUDE: Up to 13,000 feet (4000 meters). SIZE: 72"H X 28"W X 30"D (1830 mm X 712 mm X 762 mm). WEIGHT: (Unpacked) 500 lbs. (230 kg) - approximate. Domestic packed, 700 lbs. (320 kg) -

approximate. Export packed, 800 lbs. (370 kg) - approximate. CUBAGE: 68.7 cubic feet (2 cubic meters) packed. NOTE: ALL SPECIFICATIONS TAKEN WITH TRANSMITTER CONNECTED TO TEST LOAD. SPECIFICATIONS SUBJECT

TO CHANGE WITHOUT NOTICE.

1-4 888-2314-001 Rev. T: Jan. 1996

WARNING: Disconnect primary power prior to servicing.

SECTION II

INSTALLATION/OPERATION

2.1. Introduction

This section of the technical manual provides detailed installation procedures and setup instructions for the GATES Series™ AM transmitters.

Under normal conditions, the GATES Series™ T ransmitters are shipped completely assembled and ready for installation. However ,if adverseshipping conditions are anticipated, certain components may be removed for transport in which case these components will be properly identified with appropriate instructions for reinstalling the components and making wiring connections.

2.2. Unpacking

Carefully unpack the transmitter and perform a visual inspection to determine that no apparent damage was incurred during shipment.Retain theshippingmaterialsuntil ithas been determined that the unit isnot damaged. The contents of the shipment should be as indicatedonthePackingCheckListwhich accompanies each shipment. If the contents are incomplete or if the unit is damaged electricallyormechanically ,notifytheCARRIER and HARRIS CORPORATION.

2.3. Returns and Exchanges

Damaged or undamaged equipment should not be returned unless written approval and a ReturnAuthorizationisreceivedfrom HARRIS CORPORATION, Broadcast TransmissionDivision.Special shipping instructions and coding will be provided to assure proper handling. Complete details re garding circumstances and reasonsforreturnaretobeincludedinthe requestforreturn.Customequipmentorspecial order equipment is not returnable. In those instances where return or exchange of equipment isat the request of the customer ,or conv enience ofthe customer,arestockingfeewillbe charged. Allreturnswill be sent freightprepaidandproperly insured by the customer .When communicating with HARRIS CORPORATION, Broadcast Transmission Division, specify the Factory Order Number or InvoiceNumber.

2.4. General Installation Information

The GATES Series™ Transmitters have been designed for rapid installation. In addition to the 28 inch width by 30 inchdepth of the equipment, a minimum of 24 inches should be allowed for maintenance access from both the front and rear of the cabinet. Signal and power wires can be connected through several different entries or any desired c ombination thereof.

The holes for cable entrance are 2 inches in diameter, and are located at the front and rear bottom of each side panel. These entriesprovidea means to entertheequipment with wires that are then routed into the base of the equipment.

Input powerwiresshouldrun to the terminal board installed in the base of the transmitter. Access to this terminal board is gainedby removing the coverplate overthe face of the contactor chassis. The screws holding the chassis must then be removed and the chassis pulled forward.

The normal air flow through the transmitter is taken in through the back of the unit (at the bottom of the cabinet). Maximum temperature at the base of the transmitter should not be more than 50°C. The air moves from the base of the cabinet into the side panels and into themain enclosure. Air passes over the heat sink fins in the side panelsand exits through the holes inthetop ofthe cabinet. This providesefficientchimney action cooling of all the Power Amplifier and Modulator transistors.

The air that enters the main enclosure passes directly over the components dissipating heat and exhauststhroughtheoutput coils and out the top of the transmitter. The circuit cards and their heat sinks have been designed to provide a chimney action to the maximum extent practical.

NOTE

Note that the two blowers have separate

air intakes. One is filtered and the other

is not. The unfiltered side is dedicated to

the PA side wall. No filter is needed be-

cause most of the air passes through the

heat sink fins. A small amount of air is

channeled in the cabinet to flush the PA

Toroids. At approximately one year in-

tervals, the PA heat sink fins should be

inspected and cleaned. They may be re-

moved by removing the 10/32 mounting

screws.

2.4.1. Power Distribution for Optimum

Transmitter Performance

(This section is applicable to the three phase GATES FIVE only, as well as other three phase equipment.)

For many years HARRIS engineers have recommended that the three phase power distribution system should be either a closed delta or W YE configuration to provide better radio and television transmitter performanceby helping preventlineunbalance. Operation with substantial voltage unbalance from line toline results in higher

than normal signal-to-noise ratio in the transmitter output signal, increased three phase transformer heating, and hot three phase motors.

2.4.1.1. Overheating from Line Unbalance

Evenadeviceassimpleasathreephase motor should be operated from a power line in which the voltage is balanced within 1%. It takes only a 3.5% line unbalance to produce a 25% increase above normal temperature. A 5%unbalancewillcausedestructivetemperature rises of 50% greater than normal!

Similar characteristics can be expected in the windings of a three phase power transformer down inside the cabinet of your transmitter. Transformers and motors can be designedwithextrasafetyfeatureswherethermal rise is limited to acceptable levels; however ,in this case, other transmitter parameters cannot be made acceptable at a reasonable cost.

2.4.1.2. Transmitter Noise Performance

The most difficultparameter to meet with power line unbalance is transmitter noise performance. Most large transmitters use six-phase or twelve-phase high voltage power supplies. The energy storage capacitors are expensiveto install and largestored energiesmake destructive faults inevitable. A good design will have sufficient energy storage capacitors to meet thespecifiedsignal-to-noise but not much more. When the equipment is then operated from an unbalanced line, the power supply ripple frequency will be twice the line frequency instead of six to twelve times. It becomes obvious that it would take three times as much energy storage to achieve the original performance goal.

2.4.1.3. The Causes of Line Unbalance

How does a line unbalance occur? It is a rare case in w hich a large commercial powerproducer would generateunbalanced voltage, so we must look elsewhere in the system. When you have large single phase power u sers on a power line this can cause uneven distribution of the line currents in the system. Uneven currents through balanced impedances will result in line-to-line voltage unbalance.

Another likely source of this problem can come from unbalanced impedances in the power distribution system. Unbalanced impedance will always be seen when an “open” delta three phase distribution system is used. Transformer design textbooks

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WARNING: Disconnect primary power prior to servicing.

clearly show that the voltage regulation of an unbalanced system is poor.

2.4.1.4. Three Phase Delta Distribution

Transformers

Figure 2-1 shows open and closed delta systems. The closed delta impedance looking into each terminal (A, B & C) is exactly thesame;butthisisnotthecaseintheopen delta configuration. Depending on the impedances of the transformers in the open delta circuit, line voltage unbalance sufficient to impair satisfactory operation of the overall transmitter may result. For this reason, along with their inherent susceptibility to transients, Harris does not recommend the use of open delta systems.

over voltage spikes. These units are limited in the amount of energy that can be dissipated, but will handle, if designed properly, very large currents. You can’t take a direct lightning hit and still operate, but not many things will. It has been reported by engineers that installation of a thirdtransformer and trans ient protection devices, have eliminated the difficulty.

2.4.1.5. Three Phase Wye Distribution

Transformers

The WYE connected system is also considered a symmetrical form of three phase power distribution. All impedances are balanced as seen from each terminal (see Figure 2-2). It is important when using a WYE connected system that the fourth wire (neutral) is connected to the mid-point of the system as shown in the diagram. When this connectionismadeit providesa path for the zerosequencecurrentsaswellasanyharmonic currents which are generated due to the rectificationof the secondary voltages.

In summary, both symmetrical power distribution systems are satisfactory because of their balanced impedances. Use either a closed delta or a four wire WYE system for maximum transmitter performance. Never use an open delta system just to cut costs it could cost dearly in the long run.

2.5. General Installation

Requirements

The key to a rapid and successful setup is careful planning prior to delivery of the system. HARRIS offers, as an option, engineering services to reviewand comment on proposedinstallations. InadditionHARRIS offers,as anoption,design,fabrication,and installation services to any required level for total integration of the system into a facility.

Lifting Equipment (Fork Lift, etc)

Hand Tools For opening wooden

Shims (2" by 2") Aluminum,assorted

Hand Operated Hole Punch

900 lbs (408 kg) capacity

crates

thicknesses For adding 0.25"

hardware holes to

0.020" thick copper ground strap at transmitter ground connection.

Figure 2-1. Three Phase Delta

Distribution Transformers

The only advantage of the open delta is lower initial cost, and this is partiallyoffset by the fact that when only two transformers are used, they must be larger than the three transformers in a closed delta system.

Difficulties have often been experienced with open delta systems; but when a third transformerwasaddedtoclose thedelta,the problems disappeared.

Thereisanother problem which can occur with an open delta system, and that i s caused by lightning and switching transients. When lightning strikes or heavy loads are switched on a power distribution system, high voltage transients are propagated throughout the system. Unbalanced impedances will enhance these transients and can cause transmitter damage, particularly to solid state rectifiers.

Many transmitters are located at the end of a long transmission line which is highly susceptible to transient phenomena. Devices such as Metal Oxide Varistors are inexpensive and very effective in reducing

Figure 2-2. Three Phase WYE

Distribution Transformers

Today, many transformers are supplied with all of the primary terminals available sothateitheradeltaor WYEconnectioncan be made. Table2-1 shows the different lineto-line voltages that are available with this configuration.

Delta connected

transformer

WYE connected

transformer

210 364

220* 380*

230 400

240* 415*

250 433

* Typical voltages in some areas of the world.

Table 2-1. Typical Line Voltages

Delta or WYE

Table 2-2. Special Installation

Tools and Equipment

Tra ns forme r, Low

472 1678 000 (1)

Level,A20T01 Transformer,

Power,A19T01

Table 2-3. Equipment Supplied with

Transmitter and Listed on Packing

Check List Supplied with Transmitter

2.5.1. Equipment Placement

See packing list for part number

The transmitter should be located to permit adequate maintenance access and sufficient ventilation. Primary AC power cables can enter the transmitter at a variety of locations and the specific location of entry will need to be determined on site. The grounding strap between the transmitter and the station earth ground must be properly connected before AC power wiring is attached to transmitter.

2.5.2. Pre-Installation Inspection

Prior to performing the installation of the GATES Series™ transmitter, it should be thoroughly inspected for any connections which may have loosenedduring shipment.

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WARNING: Disconnect primary power prior to servicing.

This is important due to numerous high current connections in the transmitter.

Also check that all ribbon cablesare properly locked into their respective printed circuit board connectors.

The mechanical interconnecting integrity of the above mentioneditems is essential to the attaining of proper transmitter operation. Although appropriate packaging and shipping precautions are taken prior to the equipment leaving the factory, hardware may, in isolated cases, work loose in transit and result in a failure.

Check for debris or loose hardware, especiallyaroundthe high current power supply connections.

2.5.3. Equipment Positioning

Following removal of the shipping material, move the cabinet on its skid as near as possible to its permanent position. If shipping bolts have been used, they will be locatedateachcorneroftheskid.Remove the bolts from the underside of the skid.

NOTE

Positioning of the cabinet is to be per-

formed by experienced personnel to pre-

vent damage to the equipment or injury

to personnel.

With a suitable lifting device, raise one end of the transmitter cabinet sufficientlyto permit the placing of three lengthsof circular bar stock under the cabinet. In this manner the cabinet can be efficiently and carefully rolled off the skid.

2.5.4. Ground Strap Installation

The importance of a good groundingsystem and lightning protection can hardly be overemphasized for reasons of personnel safety, p rotection of the equipment, and equipment performance. The following is only a brief overview.

Lightning and transient energy via the powerline or towerconnectionscanimpose serious threats to your personal safety as well as damage the equipment. For these reasons you should have a good protective earthing system to divert these forms of energyto earth ground.Propergrounding of theequipmentalso guards against electrical shock hazards that would exist if the equipment failed in a way which put a hazardous voltage on the chassis.

A good grounding system should include substantial grounding at the tower base usingcopper ground rods and/or a buriedcopper ground screen, with copper strap used to connect the tower base to earth ground. A low impedance will help carry lightning current directly into the ground instead of into your building. Additionally, coax shield(s)should be electricallyconnectedto

and exit the tower as near to the bottom as practical to minimize the lightning voltage potential carried by the coax into your building.

For coaxes, a singlepoint of entry into the building is best, with all connected to a common grounding plate (or bulkhead panel) having a low impedance connection tothebuildingperimeter ground.Widecopper straps should be used for making the connection from the common grounding plate to earth ground.

Acommongroundingplate is alsothebest locationfor coaxialsurgeprotectorsforsensitive equipment such as an STL receiver. Ideally, this plate should also be the entry point for all signal lines, and serve as a single point ground for AC power surge protection.

A good ground system should include perimeter grounding of the transmitter building using copper ground rods and copper strap. There should also be a copper strap running from tower ground to the building perimeter ground.

Good grounding and shielding will help keep stray RF current to a minimum. RF interference usually shows up in one of several ways, intermittent problems with digital or remote control circuits, audio feedback or high pitched noise. Even a smallamountofnon-shieldedwiremakesa very efficient antenna for RF and transient energy. If RF is allowed into the audio equipment,itcanberectifiedand may show up as noise or feedback. Wire and cable shields should normally be connected at both ends to the equipment chassis.

Agroundstrapattachment point islocated on the bottom, right rear, of the cabinet behind the dust cover (uses a 10-32 brass screw with brass washer). Use this connectionwhenutilizingasinglepointgrounding system, attaching your ground strap to the common grounding plate. See 839-7920044 Gates series Outline drawing.

A groundingstud is also providednearthe AC input connections in the lower portion of the transmitter. Use this connection for the power line ground. It is located under the low voltage power supply board.

2.6. Electrical Installation

NOTE

All GATES Series™ transmitters are

shipped with A19T1 and A20T1 con-

nected for 251 VAC operation. It is ad-

vised that the end user determine the ap-

propriate tap settings during the initial

turn-on. In this procedure, the trans-

former tapping is determined by the re-

sulting DC supply voltage. This ensures

that the DC supplies are operated in the desired range.

2.6.1. Power Requirements

The GATES Series™ GATES FIVE (3 phase version) is designed to operate from a3phase,208/240 VAC,50to60 Hz source. Sixty ampere service is required. Use 6 gauge wire for this connection.

The single phase GATESFIVE requires a 100 amp 208/240 VAC, 50 to 60 Hz source. Use 4 gauge wire for this connection.

The GATES TWO requires a 60 amp 208/240 VAC, 50 to 60 Hz source. Use 6 gauge wire for this connection.

The GATES ONE requires a 30 amp 208/240 VAC, 50 to 60 Hz source. Use 8 gauge wire for this connection.

There is no requirement for 120 VAC in any case.

As an option, the low voltage circuits can be powered from a separate circuit breaker. Although not a requirement, thissetup sometimes is advantageous for maintenance and troubleshooting. If you choose to wire your transmitter this way,you will need to provide a separate 10 amp circuit breaker.

NOTE

If service voltage is less than 208 VAC,

a higher current service may be needed.

Refer to the Outline drawing for mechanical dimensions and wire feed locations.

WARNING

ENSURE THAT ALL AC POWER IS OFF PRIOR TO STARTING THE FOLLOWING INSTALLATION

2.6.1.1. Procedure.

For a three phase GATES FIVE, connect 3 phaseACinput powerfromafuseddisconnect box or circuit breaker to transmitter cabinet terminal board TB1 terminals 1, 2 and 3. The powersourcecan be either a closeddelta(usually 230 to 240 volts) or aWYE (usually 208).

For a four wire WYE system (341 to 434 volts), connect the neutral wire to terminal board TB1 terminal 4. Also for a WYE system ensure that the high voltage transformer has been tapped correctly for the configuration (see the Wiring Diagram for the three phase GATESFIVE transmitter).

For the GATES ONE, GATES TWO, or single phase GATESFIVE, connect ACinput power(197 to 251 VAC)from afused disconnect box orcircuit breaker to transmitter cabinet terminal board TB1 terminals 1 and 2.

NOTE

Terminal board TB1 is accessed by remov-

ing the four screws which hold the circuit

breaker panel to the front of the transmit-

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WARNING: Disconnect primary power prior to servicing.

ter and then sliding the circuit breaker panel forward. Terminal board TB1 is located on the floor of the transmitter directly below the AC Power panel. Terminals are numbered left to right.

Ifyou choose towireyourtransmitterwith separatelow voltageandhigh voltagefeeds, you will need to remove the factory installedjumperwiresfrom TB1, and connect a10ampservicetoTB1terminals5and6.

For the 3 phase GATESFIVE, ensure that the Phase Monitor relay A19K3 is installed

Table 2-4. Interface Board Connections

CONTROL

INPUTS TERMINAL

Low TB2-1 Two TB2-2 Three TB2-3 Four TB2-4 Five TB2-5 High TB2-6 Off TB2-7 Raise TB2-8 Lower TB2-9 Ext Kill (RF mute) TB2-10 FAILSAFE TB1-1 and TB1-2

METERING

OUTPUTS TERMINAL

PA Voltage TB2-11 PS Current TB2-12 Power Output TB2-13 STATUS TERMINAL Low TB2-15 Two TB2-16 Three TB2-17 Four TB2-18 Five TB2-19 High TB2-20

OVERLOAD

STATUS TERMINAL

Overload Ind Reset TB2-14 Auto Cutback TB2-21 Supply Voltage TB2-22 Supply Current TB2-23 Underdrive TB2-24 VSWR TB2-25 Audio TB2-26 Audio TB2-27 Ground TB2-28

in the AC Power panel and is adjusted to MIN.SeeNotebelow.

NOTE

To adjust the Phase Monitor, remove all power from transmitter and rotate the voltage adjustment screw to your approximate AC line voltage. The actual setting will have to be determined by trial and error. Refer to paragraph 2.7.1.g for adjustment information.

2.6.2. RF Output Connection

Connect the output transmission line from theantennato theRFOUTPUTconnectorjack J1 located on top of the transmitter cabinet.

A GATES ONE requires a male type N connector. Specific type N connectors are availablefor various types of coax.

TheGATESTWOandGATESFIVErequire a 7/8 EIA flange. Specific connectors of this type are available for various kinds of coax.

2.6.3. Battery Installation

The purpose of the battery on the Controller board (on the swing out panel) is to maintain transmitter operational status during a power interruption. It is not important to install it until

you are nearly ready to put the transmitter into regular operation. The transmitter will operate properly without the battery, however , po wer interruptions lasting more than a few seconds will result in an OFF condition, and all overload lights lit.

A standard 9 volt battery will last about 2 weeks of continuous running with no AC powerapplied.Alkalinebatterieswillgivethe longest shelf life. It is a good idea to change the battery after a long outage or yearly.

2.6.4. Audio Input

Route the audio cable up from the base of the transmitter to the Interface board. The Interface board is located in the lower left portion of the transmitter in the front. Connecttheaudioinputwiresto terminals TB226 and TB2-27 on the Interface Board. TB2-28is ground for the audiocable.Refer to Table 2-4 and Figure 2-3.

2.6.5. Remote Control

Allremote controlconnectionsaremadeatthe Interfaceboard. Cabling forremotecontrolmay be routed up from the base of the transmitter.

To prepare wire, strip insulation back approximately 1/4" and twist strands back into

their natural position.

A small flat blade screwdriveris an appropriate tool to use to make the connection.

To make connection, align wire in side opening “B” and depress clamp down from opening “A”with tool. Insert wire or component in opening “B” andsecurebywithdrawing tool.

Figure 2-3. Making Connections to WAGO Block

2-4 888-2314-001 Rev. AC: 2/29/00

WARNING: Disconnect primary power prior to servicing.

Note:Allremotecontrol inputs areactivated by applying a momentary ground connection to each desired input. This makes the transmitterdirectlycompatiblewithopencollector type remote control units as well as dry contact systems. With a dry contact (relay) system, you will simply need to momentarily switch each of the desired control inputs to ground in order to cause a function to occur.

The status outputs for power levels and overloads are open collector outputs. These are directly compatible with TTL type inputs,or may be usedto drivesmallrelays or other indicating devices as long as the current requirements are 100 ma or less.

To use a status output to drive a small relay, you will need to connect the relay from the status output toa DC power source with a positive voltage between 5 volts and 24volts.As with anyDCpoweredrelay,you should connect a diode across the coil, with the cathode toward the positive supply.

2.6.6. Airflow Sensor Status

In addition to the status outputs described above, transmitters manufactured December 1995 and later are equipped with an Airflow Sensor circuit which includes a status output. A relay contact closure is providedonTB1onthemainAirflowSensor circuit board, located in the air inlet for A20B1.

All metering samples are positive with respect to ground and are less than 5 volts into a 10k ohm input resistance.

2.6.7. Failsafe Connection

24VAC contactor coil current passes through the Failsafe Interlock t ermi nals. Therefore, high voltage power supply activationrequires the presence of a continuous closure across the Failsafe Interlock terminals. Opening of the contacts results in deenergizing the HV contactors.

A connection is required at the Failsafe terminals even if the transmitter will be locally controlled. Switching the transmitter to Local control does not bypass the Failsafe interlock.

Contacts and wiring connected to these terminalsshouldberatedfor atleast24 VAC @ 1 amp. Refer to the listing of Interface Board connections in the Table 2-4.

The shield connection forthe remote controlcablingshouldbe connected to a nearby ground stud or one of the Interface board mounting screws.

2.6.8. Modulation Monitor Sample

An adjustable, 1 to 5 Volt RMS signal source is provided on the Output Monitor board.The Output Monitor board is located behind an access door on the front. Route

the cable for the modulation monitor from the base of the transmitter up to thelocation of the Output Monitor board. The coax will slip into the gap between the transmitter wallandtheenclosurefortheOutputMonitor, RF Oscillator, and PDM Generator.

Connect modulation monitor to the BNC jackon theOutputMonitorboardA18.Besure topositionthecoaxsafelyawayfromany components which may generate enough heat to melt the insulation on the coaxial cable.

2.7. Initial Turn On Procedure

Before initial t urn on, ensure that the following items are checked:

a. Ground strap is properly connected be-

tween tran smitter and station earth ground.

b. Check for debris/hardware in base of

transmitter and in AC Panel.

c. Make sure all hardware connections are

tight. d. AC input wiring is properly connected. e. Transmitter output is properly termi-

nated into a suitable load capable of

handling rated output power (antenna or

dummy load). f. Audio input is properly connected. g. Monitoring equipment is properly con-

nected. h. The REMOTE/LOCAL switch on the

Controller board (on the swing out

panel) should be in the local mode. i. Be sure the front and rear covers are in

place.

2.7.1. Initial Turn On

Important

Temporarily remove F1 from the Interface board. This will disable the contactor circuit for the first part of the turn-on procedure. Fasten the bottom frontpanel in place with at least two screws.

WARNING

THE NORMAL PROCEDURE FOR TRANSMITTER TURN OFF SHOULD BE FOLLOWEDINORDERTOPROPERLY DISCHARGE THE HIGH VOLTAGE COMPONENTS. TURN OFF THE HIGH VOLTAGEBYDEPRESSING THEOFF BUTTON. IFYOUMUSTENTERTHETRANSMITTER, SET THE REMOTE/LOCAL SWITCH TO LOCAL AND ALLOW THE POWER SUPPLY TO DISCHARGE AS INDICATED BY THEFRONTPANEL METERS. LOWVOLTAGE MAY THEN BE REMOVED BY SETTING THE LOW VOLTAGE CIRCUIT BREAKER TO OFF. DISCONNECT ALL PRIMARY POWER SERVICE. REMOVE THE REAR LIFT OFF PANEL SLOWLY TO ALLOW THE RESISTOR DISCHARGE MECHANISMTOFUNCTION.AGROUNDING STICK IS PROVIDEDIN THE TRANS-

MITTER AND SHOULD BE USED TO ASSURE THAT ALL HIGH VOLTAGE HAS BEEN REMOVED UNDER FAULT CONDITIONS. BE CAREFUL NOT TO GROUND ANY CONNECTIONS WHICH ARE STILL ENERGIZED.THISWOULDINCLUDE ALL LOW VOLTAGE CIRCUITS IF THE LOW VOLTAGE CIRCUIT BREAKER HAS NOT BEEN SET TO OFF POSITION.

CAUTION

IF ANY ABNORMALITIES ARE ENCOUNTERED IN THE FOLLOWING STEPS, STOP THE PROCEDURE, REMOVE ALL POWER, AND PROCEED TO TROUBLESHOOTING SECTION OF MANUAL.

a. Using a small blade screwdriver or ad-

justing tool, rotate the LOWpowerlevel control pot (located below the LOW powerON switch)severalturns counterclockwise. The other pots may be left at

the factory settings for now. b. Apply AC power to transmitter. c. Set the LOW VOLTAGE circuit breaker

A20CB1 to ON position. d. Verify the +/- 12 volt supply LED’sillu-

minate on the control panel. e. If you havea3 phase GA TESFIVE,verify

red LED on Phase Monitor (inthe contac-

tordrawer) isilluminated.Ifthe LEDisnot

illuminated, either the Phase Monitor is

not adjusted for the correct line voltage or

thephasesequenceis backwards.Remove

all po wer and adjust the volta ge selector

on the Phase Monitor to the lowest setting

and re-apply power. f. If the LED is still not illuminated, re-

move all power and reverse any two

leads in the main disconnect box and

re-apply power and verify that the LED

is illuminated. Adjust the voltage selec-

tor so that the red LED on the Phase

Monitor relay illu minates when AC

power is applied. In this adjustment, al-

low for a reasonable sag in line voltage,

butdo not desensitize it so far that itwill

be ineffective.

Note: The Phase Monitor relay adjustment is affected only by the particular line voltage.Itisnot affectedbythe changing of transformer taps which may be done later.

g. Install screws holding AC Power panel

in place.

WARNING

ENSURE ALL VOLTAGE IS REMOVED FROM TRANSMITTER AND ALL POINTS WHERE VOLTAGE HAS BEEN APPLIED ARE GROUNDED BEFORE CHANGING ANY TAPSIN THE FOLLOWING STEP.

h. Use a suitable voltmeter to measure the

+/-20voltsupply. A convenientpointfor checking these voltages is on the PDM

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WARNING: Disconnect primary power prior to servicing.

Generator, A15 at the fuses. Measure each voltage with respect to ground. If the voltages are under 19 Vdc, disconnect AC power and re-tap A20T1 to the nextlowerprimary voltage(taps240,0).

It is desired thatthe low voltage supply be between 19 and 23 Vdc both plus and minus. Use a procedure of removing AC power, grounding transformer taps, moving the primary wiring to the next lower increment, then measuring +/-20 volt supplies, to achieve the desired supply voltages.

Note: The transformer tap connections are provided on TB3, terminals 15 through

19. Refer to Figure 2-3 for instructions on using the Wago block terminals. Move the AC connection as deemed appropriate to achieve the desired output voltage.

i. Verify that all overloadand fault indica-

tors can be extinguished by pressing the Reset button.

j. Check theRFDrivereadingontheMul-

timeter. It should be close to the values recorded on the factory test data sheet. If it is not, re-check the low voltage transformer tapping. If needed, check the actual RF Drive on the PA module(s) per the procedure in Section C.

k. Confirm that when any of the power ON

pushbuttonsaredepressed theyilluminate. The AC contactors in the pull out drawer should not be heard energizing at this time sinceF1isnotinthe Interfaceboard.Also, thePDMKILLandPDMFAULTLED’s will light in this condition.

l. Verifythat depressing the OFFpushbut-

ton clears all power ON pushbuttons.

m.Disconnect all primary power, and in-

stall F1 in place on the Interface board. n. Reapply primary power. o. Rotate the multimeter switchto theSup-

ply Voltage position. Depress the LOW

power pushbutton. The contactors

should close and apply main ACvoltage

tothehigh voltagesupply.Themultime-

ter should show a voltagein the rangeof

220 to 270 on the 300 scale.

WARNING

IF CONTACTORS DO NOT CLOSE IN THE PRECEDING STEP, REMOVE ALL POWER FROM TRANSMITTER AND ENSURE FAILSAFE INTERLOCK CONTACTS ARE JUMPERED OR EXTERNAL FAILSAFE HIGH VOLTAGE INTERLOCK CIRCUIT IS PROPERLY CONNECTED. ALSO BE SURE THE REAR PANEL IS SECURELY FASTENED.

p. Switch the multimeter to read Detector

Nullandverifythatthereadingiszero. q. Rotate the LowPowercontrol potclock-

wise and observe the PA Voltage, PA

Amps, and FWD Power meters, and raise the power until the power level is as stated on the factory Final Test Data Sheets for the Low Power setting.

r. If the Detector Null reading increases

from zero, adjust the TUNING and LOADING controls to minimize the reading. This will match the PA to the load impedance you are using.

Duringtheinitial tune-up, the null should be found to be well withinthe range of the TUNING and LOADING controls. If these controlsrequire considerable adjustment,theload impedance on the transmitter is probably not very close to 50 ohms. Ifconsiderable adjustment is required, the impedance presented to the transmitter output terminal should be measured and corrected as necessary.

Although the transmitter is designed to match up to a 1.5:1 VSWR, the optimum condition is to terminate it into 50 ohms.

s. Depress Power Level number 2. The

power level should increase to near the factory setting for this power level. It probably will not be exactly the same since the Fine Power adjustment has not been made.

t. AdjusttheTuningand Loading controls

as necessary to null the Detector Null readingtozero.

u. Compare the present readings against

thefactorydataforanymajordiscrepancies. If any exist, it should be investigated at this time.

v. Progressively step the power level up-

ward by selecting each higher level, check the readings against the Final Test Data Sheets. Adjust the TUNING and LOADINGcontrols to minimize the Detector Null reading to zero.

w.Compare all readings against the Test

Data. Since the High Voltage transformer is tapped at 240 +11 from the factory, it will probably be necessary to changethetransformertapsaccordingly. The need to do this or not is determined by the Supply Voltage reading on the Multimeter.Itshouldbe250to265 volts at full power.

A change from one transformer tap setting to the next will produce about a 5% change in DC Supply voltage. For example, moving from 240, +11 to a setting of 240, 0 would result in a DC Supply increase of about 5%.

NOTE

The smaller gauge wiring on the trans-

former primary is for the fans. These

smaller wires should always be left on

240, -11.

If you will be operating the transmitter well below its rated power, then you may leave the High Voltage transformer at it

highest primary setting. This will yield the best overall performance if it is to be operating at a reduced power level.

WARNING

ENSURE ALL VOLTAGE IS REMOVED FROM TRANSMITTER AND ALL POINTS WHERE VOLTAGE HAS BEEN APPLIED ARE GROUNDED BEFORE CHANGING ANYTAPS ONTHETRANSFORMER.

x. Look at the range of the Fine Power

adjustment using the Raise/Lower switches. It is desirable to seteach of the coarse power level pots (LOW through HIGH) with the Fine adjustment in the middle portion of its range.

The PDM Power Level reading on the Multimeter is essentially the power control settings. This reading may serveas a handy reference for each desired power level. These readings should be recorded when the transmitter is initially set up, and used later if you need to troubleshoot a power level change.

y. Check or set each powerlevelaccording

to your needs and compare all readings with the factory test data. Report any major discrepancies to the HARRIS Service Department.

The GATES Series™ incorporates a protectiveactionnamed Automatic Cutback in which the transmitter will step to each successivelylowerpowerinanefforttostayat thehighesttolerable powerlevelwhen there is an overload condition. This is similar to the automatic foldback feature in some transmitters, but is different in that the power level steps down rather than going through a gradual reduction.

Because of the Automatic Cutback feature,it isusefulto setall6 powerlevels.This way, the transmitter output will remain at a reasonable level should an Automatic Cutback occur. These power levels that you would not ordinarilyuse may be intermediate power levels, or lowerthan your normal operating powers.

2.7.2. Modulation Monitor Carrier Level

After each power level has been adjusted, you should set the RF sample level for your Modulation Monitor. If you are not using a modulation monitor at the transmitter, you should leave all of the monitor level controls setfullycounterclockwise(minimumoutput).

The output levels of the monitor circuit are independent of one another, so they may be set in any order. While operating at a particular powerlevel,rotateeach corresponding control clockwise to achieve adequate carrier level.

Switching the REMOTE/LOCAL switch (nearthe battery on the Controllerboard)to

2-6 888-2314-001 Rev. AC: 2/29/00

WARNING: Disconnect primary power prior to servicing.

the REMOTE position will enable the remote control circuits and should be in REMOTE position for normal operation. In addition to enabling the remote inputs, the transmitter will mute the RF Oscillator when in an OFF condition.

Note: The PA Voltmeter deflects upward when shut off in the Remote mode. This is a normal function of the RF drive being removed when PA voltage is present.

2.7.3. Application of Audio

Apply audio to the transmitter, and observe the resulting modulation level on the monitor. The audio input sensitivity is factory set for +10dBm, but is continuously

adjustabledown to -10dbm. Ifyou desire to increasethesensitivity, you may adjust R21 on the PDM Generator.

Audio polarity is important, especially if youoperateinstereo. Observetheresultson yourmonitor,and change the audio polarity if the need is indicated.

2.7.4. Remote Meter Calibration

The remote sample outputs of the transmitter are designed to be compatible with mostmodernday remote controlunits,with lessthan5voltsdc of output intoa10Kohm impedance. There are no internal adjustments for these voltages.

Set the remote control unit’s calibration adjustments to match the transmitter’sme- ter readings.

Note: The remote current reading is Supply Current, which is not the same as PACurrent. The remote Supply current reading should be calibrated against the Supply Current reading on the transmitter multimeter.

Supply Current actually reads lower than PA Current in normal operation due to the manner in which the PDM system operates.

Thisconcludes the initial turn onprocedure.

Referto sections A through K for individual board controls and indicators.

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WARNING: Disconnect primary power prior to servicing.

CONTROL/INDICATOR FUNCTION Power TransformerA19T1 Main Power Supply transformer for 260 volt dc supply. PDM Pullup Resistors Shield shown covering 250 watt resistor(s) used by PDM Pull-up circuits. Low Voltage Transformer A20T1 Secondary for +20VDC, -20VDC, 24 VAC, and IPA Supply (60/75/90/105/120 Vdc).

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WARNING: Disconnect primary power prior to servicing.

Figure 2-4. Base of GATES Transmitter

Table 2-5. Base of GATES Transmitter

CONTROL/

INDICATOR FUNCTION

Relay K1 Relay K1 is used to

applyACtothehigh voltage transformer through current limiting resistor(s) during the step start sequence.

Relay K2 Relay K2 is used to

apply ACmains directly to the high voltage transformer.

Terminal Board TB1

Step Start Resistors A19R3, A19R2, & A19R1

Provides connections for AC input power.

(Only one resistor is used in the single phase transmitter.) The step start resistors limit the power supply surge currenton initial turn on.

Phase Monitor Detects loss of phase on

primary AC input power and h as capability to detect low primary AC input voltage (3 phase GATES FIVE only).

FAN C ircuit Breakers A20CB2 &

Protect wiring to fans from over current condition.

A20CB3 Lamp A20DS1 DS1 will illuminate

whenpoweris applied to thelowvoltagecircuitry.

Circuit Breaker, CB1

10 Amp circuit breaker to protect the low volta g e power supply from an over current condition.

Lamp A19DS1 A19DS1 will illuminate

when power is applied from the Main Disconnect Switch (i.e. cabinet is receiving AC power).

Figure 2-5. AC Power Panel

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WARNING: Disconnect primary power prior to servicing.

Table 2-6. AC Power Panel

Controls and Indicators

Table 2-7. GATES ONE

Typical Readings at 1340kHz

Power Output 1000W 800W 600W 400W 200W 100W PA Volts 92.5 84 74 62 46.5 35 PA Amps 12.5 11.3 10 8.4 6.4 4.9 PDM Level 6.4 5.8 5.1 4.3 3.2 2.4 Supply Voltage 242 244 246 248 252 254 Supply Current 4.8 4.1 3.3 2.5 1.6 1.1 RF Drive 7.4 7.4 7.4 7.4 7.4 7.4 VSWR Detector Null 0 0 0 0 0 0 VSWR Detector Null Set 5.3 5.3 5.3 5.3 5.3 5.3 Underdrive Set 6.4 5.8 5.1 4.3 3.2 2.4 Supply Current Set 8.3 8.3 8.3 8.3 8.3 8.3 Supply Voltage Set 297 297 297 297 297 297 Battery 9.8 9.8 9.8 9.8 9.8 9.8 The readings above are typical readings. Refer to the Factory Test Data Sheets supplied for readings actually obtained during factory

tests.

Table 2-8. GATES TWO

Typical Readings at 800kHz

Power Output 2500W 2000W 1500W 1000W 500W 200W PA Volts 98.5 90.0 79.0 66.0 50.0 35.0 PA Amps 28.7 26.1 23.0 19.0 14.0 10.0 PDM Level 6.8 6.2 5.5 4.6 3.4 2.4 Supply Voltage 249 250 252 257 260 265 Supply Current 12.0 10.0 8.0 5.0 3.0 2.0 RF Drive 8.9 8.8 8.8 9.0 9.0 9.0 VSWR Detector Null 0 0 0 0 0 0 VSWR Detector Null Set 6.6 6.6 6.6 6.6 6.6 6.6 Underdrive Set 6.7 6.2 5.5 4.5 3.4 2.4 Supply Current Set 23.5 23.5 23.5 23.5 23.5 23.5 Supply Voltage Set 299 299 299 299 299 299 Battery 9.8 9.8 9.8 9.8 9.8 9.8 The readings above are typical readings. Refer to the Factory Test Data Sheets supplied for readings actually obtained during factory

tests.

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WARNING: Disconnect primary power prior to servicing.

Table 2-9. GATES FIVE

Typical Readings at 920kHz

Power Output 5000W 4000W 3000W 2000W 1000W 500W PA Volts 96.0 87.0 76.0 62.0 48.5 37.0 PA Amps 57.5 52.5 46.0 38.5 29.5 22.5 PDM Level 6.7 6.0 5.3 4.5 3.4 2.5 Supply Voltage 247 250 252 255 259 262 Supply Current 24.1 20.0 15.8 12.0 6.8 4.2 RF Drive 8.7 8.7 8.6 8.5 8.4 8.3 VSWR Detector Null 0 0 0 0 0 0 VSWR Detector Null Set 5.1 5.1 5.1 5.1 5.1 5.1 Underdrive Set 6.7 6.0 5.3 4.4 3.3 2.5 Supply Current Set 44.8 44.8 44.8 44.8 44.8 44.8 Supply Voltage Set 297 297 297 297 297 297 Battery 9.8 9.8 9.8 9.8 9.8 9.8 The readings above are typical readings. Refer to the Factory Test Data Sheets supplied for readings actually obtained during factory

tests.

Rev. AC: 2/29/00 888-2314-001 2-11

WARNING: Disconnect primary power prior to servicing.

2-12 888-2314-001 Rev. AC: 2/29/00

WARNING: Disconnect primary power prior to servicing.

SECTION III

MAINTENANCE

3.1. Introduction

This section provides preventive maintenance information and corrective maintenance procedures. The information contained in this section is to provide guidance for establishing a comprehensive maintenance program to promote operational readiness and eliminate down time. Particularemphasis is placed on preventive maintenanceand record-keeping functions. For further information on maintenance of particularboard, refer to sections A through K.

3.2. Station Records

The importance of keeping station performance records cannot be overemphasized. Se parate logbooks should be maintained by operation and maintenance activities. These records can provide data for predicting potential problem areas and analyzing equipment malfunctions.

3.2.1. Maintenance Logbook

The maintenance logbook should contain a complete description of all maintenance activitiesrequired to keep the equipment in operationalstatus.A listing of maintenance information to be recorded and analyzed to provide a data base for a failure reporting system is as follows:

DISCREPANCY Describe the nature of the malfunction including all observable symptoms and performance characteristics. CORRECTIVE ACTION Describe the repair procedure used to correct the malfunction. DEFECTIVE PART(S) List all parts and components replaced or repaired and include the following details:

a. Time In Use B. Part Number C. Schematic Number D. Assembly Number E. Reference Designator

SYSTEM ELAPSED TIME Total time on equipment NAME OF REPAIRMAN Person who actually made the repair STATION ENGINEER Indicates Chief Engineer noted and approved the repair of the equipment

3.3. Preventive Maintenance

Preventive maintenance is a systematic series of operations performed periodically on equipment. Because these procedures cannotbe applied indiscriminately,specific instructions are necessary.Preventivemain-

tenance consists of six operations: inspecting,feeling,tightening,cleaning, adjusting, and painting.

INSPECT. Inspection is the most important preventive maintenance operation because it determines the necessity for the others.Become thoroughlyacquaintedwith normaloperatingconditionsin order to recognize and identify abnormal conditions readily. Inspect for the following:

Overheating, which is indicated by discoloration, bulging of parts, and peculiar odors. Oxidation. Dirt, corrosion, rust, mildew, and fungus growth.

FEEL. Use this operation to check parts for overheating. By this means the lack of proper ventilation or the existence of some defect can be detected and corrected before serious trouble occurs. Become familiar with operating temperatures in orderto recognize deviations from the normal range.

TIGHTEN. Tighten loose screws, bolts, and nuts. Do not tighten indiscriminatelyas fittings that are tightened beyond the pressure for which they are designed may be damaged or broken.

CLEAN. Clean parts only when inspection shows that cleaning is required and only use approved cleaning solvent.

ADJUST. Make adjustments only when inspection shows that they are necessary to maintain normal operation.

PAINT. Paint surfaces with the original type of paint(using prime coat if necessary) wheneverinspectionshowsrust, or worn or broken paint film.

3.3.1. Maintenance Of Components

The following paragraphs provide information necessary for the maintenance of components.

TRANSISTORS. Preventive maintenanceof transistorsis accomplishedby performing the following steps:

Inspect the transistors and surrounding area for dirt as accumulations of dirt or dust could form leakage paths.

Use compressed dry air to remove dust from the area.

WARNING

ALWAYS WEAR SAFETY GOGGLES WHEN USING COMPRESSED AIR.

Examine all transistors for loose connections or corrosion. Tighten the transistor mounting hardware to no more than 5 inch-

pounds. Over-tightening the transistor hardwarewillcausethesiliconinsulatorsto curl up on the ends and possibly short through. When replacing a MOSFET transistor, be sure to alternate frequently between the mounting posts to tighten the hardware down evenly. This will minimize the possibility of shorting through an insulator.

CAUTION

IF THE TRANSISTORS IN THE PA OR IPA REQUIRE CHANGING, ENSURE THAT ALL OF THE TRANSISTORS ARE OF THE SAME TYPE NUMBER AND ARE FROM THE SAME MANUFACTURER.

INTEGRATED CIRCUITS.Preventive

maintenance of integrated circuits is accomplished by performing the following steps:

CAUTION

USE CARE TO AVOID THE BUILDUP OF STATIC ELECTRICITY WHEN WORKING AROUND INTEGRATED CIRCUITS.

Inspect the integrated circuits and surrounding area for dirt as accumulations of dirt or dust could form leakage paths.

Use compressed dry air to remove dust from the area.

WARNING

ALWAYS WEAR SAFETY GOGGLES WHEN USING COMPRESSED AIR.

CAPACITORS. Preventive maintenance of capacitors is accomplished by performing the following steps:

Examine all capacitor terminals for loose connections or corrosion. Ensure that component mountings are tight. (Do not over tighten capacitor mounting straps as excessive pressure could cause internal shorting of the capacitors. Examine the body of each capacitor for swelling, discoloration, or other evidence of breakdown. Use standard practices to repair poor solder connections with a low-wattage soldering iron. Clean cases and bodies of all capacitors.

Inspectthe bleederresistorswhen inspecting the electrolytic capacitors.

FIXED RESISTORS. Preventive maintenance of fixed resistors is accomplished by performing the following steps:

When inspecting a chassis, printedcircuit board, or discrete component

Rev. AD 888-2314-001 3-1

WARNING: Disconnect primary power prior to servicing.

assembly, examine resistors for dirt or signs of overheating. Discolored, cracked, or chipped components indicate a possible overload. When replacing a resistor, ensure that the replacement value corresponds to the component designated by the schematic diagram and parts list. Clean dirty resistors with a small brush.

VARIABLETUNINGAND LOADING

COILS.Lubricateat six month intervals,or

as required if binding is evident, the mating surfaces of the ribbon and wiper with HARRIS lubricant (part number 055 0115 007) using a cotton swab to apply the liquid. Follow directions provided with lubricant forproperapplicationtechniques. Use sparingly as too much may prove ineffective. This lubricant can also be obtained locally or from CAIG LABORATORIES, INC., Escondido, CA., 92025-0051 under the name of CRAMOLIN R.

FUSES. Preventive maintenance is ac-

complished by performing the following steps:

When a fuse blows, determine the cause

before installing a replacement.

CAUTION

IF ANY OF THE FUSES IN THE GATES SERIES™ TRANSMITTER REQUIRE REPLACING, ENSURE THAT ONLY AN EXACT REPLACEMENT FUSE IS USED. A DIFFERENT MANUFACTURER’SFUSEOFTHESAME SIZE AND/OR RATING DOES NOT FULFILL THE REQUIREMENT FOR EXACT REPLACEMENT.

Inspect fuse caps and mounts for charring

and corrosion.

Examine clips for dirt, and, if necessary,

clean with a small brush.

If necessary, tighten fuse clips and connectionsto the clips. The tensionofthefuse clips may be increased by pressing the clip sides closer together.

SWITCHES. Preventive maintenance of switchesisaccomplished by performingthe following steps:

Inspect switch for defective mechanical action or looseness of mounting and connections.

Examine cases for chips or cracks. Do not disassemble switches.

Inspect accessible contact switches for dirt, corrosion, or looseness of mountings or connections. Check contacts for pitting, corrosion, or wear. Operate the switches to determine if they move freely and are positive in action. Tighten all loose connections and mountings.

Be sure to include an inspection of the power supply discharge switches located at the bottom of the rear panel opening.

TOROIDS. Inspect the drive transformer

assemblies periodically for any signs of stress. These would be T11 and T12 on the IPA andT11,T12,T21, T22,T31,T32,T41, and T42 on the Power Amplifierboards A1 through A4. In particular, check the zener diodes on these transformer assemblies for signs of over dissipation. When over dissipated, these zeners will lose their normal glossy finish. If any of these zeners are found in this condition, check the RF drive system.

Thetoroidson the backsideof the IPAand PA should be inspected when the modules are removed for replacing transistors. A crack or break in any core may cause damage to the transistors of the same quad. The best way of inspecting the toroidal cores is by rotating the core. This will allow a complete visual inspection.

PRINTED-CIRCUIT BOARDS.Preventive maintena nce of printed circuit boards is accomplished by performing the following steps:

Inspect the printed circuit boards for cracks or breaks. Inspect the wiring for open circuits or raised foil. Check components for breakage or discoloration due to overheating. Clean off dust and dirt with a clean, dry lint-free cloth. Use standard practices to repair poor solder connections with a 40 watt soldering iron.

CAUTION

ENSURE THAT THERMAL COMPOUND IS APPLIED TO PLATES OF PA, IPA, AND PDM AMPLIFIERBOARDSBEFORETHEYAREINSTALLEDON HEAT SINKS AND THAT HARDWARE SECURING BOARD TO HEAT SINK IS PROPERLYTORQUED TO 6-INCH POUNDS. ALSO INSURE NO BURRS OR DIRT PARTICLES ARE ON THE MATING SURFACES.

3.3.2. Air System

The air filter should be cleaned routinely. The intervalsbetween cleaning will depend on the environment.

Replace filter if it is worn out.

3.3.3. GATES Series™ Top Removal

Procedure

The GATES Series™ top may have to be removed to change frequency determinant components if a frequency change is required, or any capacitors need replacing.

WARNING

ENSURE ALL POWERIS REMOVED AND NETWORK COMPONENTS ARE SHORTED WITH SHORTING STICK BEFORE PERFORMING THE FOLLOWING PROCEDURE.

a. Make sure all power is turned off and

Output Network components are shorted to ground with shorting stick.

b. Disconnect A21L1 in the Output Net-

work from PA module A1 (see Figure 3-2).

c. Remove the eight screws holding RF

shield below L2 and remove RF shield from transmitter.

d. Disconnect the tubing which connects

A21L7 to the TUNING control, L4 as showninFigure3-3.

e. Remove10-32 Phillips headscrewfrom

C3 connector strap that goes to L4 (see Figure 3-3).

f. Separate the two halves of A18P4. This

connector is in line with three coaxes which go from the bracket e nd of A21 L2 to the Output Monitor board (see Figure 3-2).

g. Disconnect gray wire #112 from the HV

shorting switch at the upper left of the rear opening.

h. Remove all of the 8-32 screws around

the perimeter oftop access panel and the eightr screws on the top rear (see Figure 3-1).

CAUTION

THE REMOVABLE TOP ASSEMBLY WEIGHS APPROXIMATELY 46 POUNDS.

i. From the rear of transmitter, pick up on

thetop and pull complete assembly back about one inch. It may be necessary to pull slightly on top back section to disengage edges from guide slots in corner posts.

j. At this point it maybe more desirable to

grasp bottom of L2 with one hand and topbacksection with the otherhand.Lift top rear about one inch and pull complete assembly straight back and then down to desired work area.

k. Reinstall the GATES Series™ top by

reversing the above procedure.

3.3.4. Low Voltage Supply Adjustment

The Low Voltage power supply outputs need to be in the desired voltage range in order for the transmitter to work properly. One Low Voltage Supply output is +/-20 volts for use by the Controller, PDM Generator, RF Oscillator, PDM Amplifiers, Output Monitor, and Interface board.

The other output from the Low Voltage Supply is for use by theIPA and is60to120

3-2 888-2314-001 Rev. AD

WARNING: Disconnect primary power prior to servicing.

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Harris 994 9202 002, 994 9203 002, 994 9204 002, 994 9205 002 Technical Manual

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Frequently Asked Questions

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