Nokia 7280 Service Manual 06(b) RM14 rf trouble

Nokia Customer Care

6(b) - RF Troubleshooting

6(b) RF Troubleshooting

Instructions

and Manual Tuning

RM-14

Nokia Customer Care RF Troubleshooting and Manual Tuning

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2 COMPANY CONFIDENTIAL ISSUE 1 11/04

RM-14 RF Troubleshooting and Manual Tuning Nokia Customer Care

Table of Contents

Page No

Introduction .........................................................................................................5

Notes on reference measurements.................................................................... 5

Helgo / Synthesizer Troubleshooting................................................................6

N500 Helgo troubleshooting .............................................................................. 7

Synthesizer troubleshooting............................................................................... 8

Tx Troubleshooting............................................................................................. 9

Tx 900 GMSK troubleshooting......................................................................... 10

Tx 1800/1900 GMSK troubleshooting.............................................................. 11

Rx Troubleshooting ..........................................................................................12

Rx 900 troubleshooting.................................................................................... 13

Rx 1800 troubleshooting. ................................................................................. 14

Rx 1900 troubleshooting. ................................................................................. 15

Bluetooth / FM Radio Troubleshooting........................................................... 16

Bluetooth troubleshooting................................................................................ 17

FM radio troubleshooting................................................................................. 18

Service Tool Concept for RF Tunings .............................................................19

Service concept for RM-14 RF tunings............................................................ 20

Receiver Tunings............................................................................................... 21

RX channel select filter calibration................................................................... 21

RX calibration................................................................................................... 22

EGSM900 band ............................................................................................. 22

GSM1800 band ..............................................................................................24

GSM1900 band ..............................................................................................25

RX band filter response compensation............................................................ 26

EGSM900 band ............................................................................................. 27

GSM1800 band ..............................................................................................30

GSM1900 band ..............................................................................................31

T ransmit ter Tunings.......................................................................................... 33

TX power level tuning ...................................................................................... 33

EGSM900 PA High Mode with EDGE off .......................................................34

EGSM900 PA high mode with EDGE on ....................................................... 35

GSM1800 PA high mode with EDGE off ........................................................36

GSM1800 PA high mode with EDGE on ........................................................37

GSM1900 PA high mode with EDGE off ........................................................38

GSM1900 PA high mode with EDGE on ........................................................39

TX I/Q tuning.................................................................................................... 40

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RM-14

Nokia Customer Care RF Troubleshooting and Manual Tuning

EGSM900 band with EDGE Off .....................................................................40

EGSM900 band with EDGE On .....................................................................42

EGSM1800 band with EDGE Off ...................................................................42

GSM1800 band with EDGE On .....................................................................42

GSM1900 band with EDGE Off .....................................................................42

GSM1900 band with EDGE On .....................................................................43

List of Figures

Page No

Fig 1 Helgo/Synthesizer........................................................................................6

Fig 2 PA/TX........................................................................................................... 6

Fig 3 Helgo/Synthesizer........................................................................................9

Fig 4 PA/TX........................................................................................................... 9

Fig 5 TX 900 GMSK troubleshooting ....................................................................10

Fig 6 TX 1800/1900 GMSK troubleshooting .........................................................11

Fig 7 Helgo/Synthesizer........................................................................................12

Fig 8 PA/TX........................................................................................................... 12

Fig 9 RX 900 troubleshooting................................................................................ 13

Fig 10 RX 1800 troubleshooting............................................................................ 14

Fig 11 RX 1900 troubleshooting............................................................................ 15

Fig 12 Bluetooth/FM.............................................................................................. 16

Fig 13 Bluetooth troubleshooting ..........................................................................17

Fig 14 FM radio troubleshooting ...........................................................................18

4 COMPANY CONFIDENTIAL ISSUE 1 11/04

RM-14 RF Troubleshooting and Manual Tuning Nokia Customer Care

Introduction

This document is the troubleshooting guide for RM-14. On the following pages you will find a step-by-step fault finding procedure and reference measurements at the relevant signal points.

Note! Most test points are not accessible unless shielding cans are cut open. This must ONLY be done by the Return Analysis technicians and for analysis only!

■ Notes on reference measurements

• LF & DC signals are measured with Textronix 100 MHz Scope (TDS3014) and P3010 13pF probe.

• RF signals are measured with R&S FSIQ 7GHz Spectrum Analyzer and Agilent resistive divider probe (10dB, 500ohm).

• Please be aware that the RF connector on service adaptor is leaking power (into air) and acts as noise source when probing on RX chain. In 1800 band the problem is most severe while there is no external LNA to amplify the signal above the noise level like in the 1900 band. In 900 band the leakage is not as high due to lower frequency.

• GSM SA settings: RBW=500kHz, VBW=500kHz.

• Bluetooth SA settings: RBW=2MHz, VBW=2MHz.

• All reference measurements were made on a RM-14 phone (GSM900).

• RF loss Module Repair Jig: 900: 0.6 dB, 1800: 1.1dB and 1900: 1 .2dB. Bluetooth is 1.8dB.

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RM-14

Nokia Customer Care RF Troubleshooting and Manual Tuning

Helgo / Synthesizer Troubleshooting

Figure 1:Helgo/Synthesizer

Figure 2:PA/TX

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RM-14 RF Troubleshooting and Manual Tuning Nokia Customer Care

■ N500 Helgo troubleshooting

N500 HELGO troubleshooting

Set Phoenix to RF local burst RX mode

Measure N500 Helgo supply voltages:

- VR1 at C551 - 4,75V?

-VR1 at C516 - 4,75V?

- VR2 at C520 - 2,8V?

-VR2 at C510 - 2,8V?

- VR3 at C503 - 2,8V?

-VR3 at C522 - 2,8V?

- VR4 at C554 - 2,8V?

-VR4 at C520 -2,8V?

- VR5 at C553 - 2,8V?

-VR5 at C518 -2,8V

- VR6 at C555 - 2,8V?

-VR6 at C521 -2,8V?

- VR7 at C297 - 2,8V? (located at BB bottom grid S3)

-VR7 at C500 -2,8V?

Measure N500 reference voltage:

VrefRF01 = 1,35V (C549)

1,44V

(C524)

Measure N500 serial bus signals

- RfBusClk at J501

- RfBusEna1 at J502

- Reset at J503

- RfBusData at J509 All measured in Burst Mode

Logic high level = 1,8V.

NOK

Check baseband.

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R420

Nokia Customer Care RF Troubleshooting and Manual Tuning

■ Synthesizer troubleshooting

Synthesizer Troubleshooting

Phoenix: RF local mode Rx continuous

Frequency = 3770.4 MHz @ ch. 38

Measure G501 VCTCXO output voltage at G501 pin 3

26 MHz 900 mVpp. OK ?

Measure N500 26 MHz reference output voltage at L515 800 mVpp. OK?

Measure G501 VCTCXO AFC voltage at C540.

Measure RF frequency and level at T500.

Place the probe through the hole in the shield!

Correct frequency found?

No frequency or wrong frequency ?

No frequency found within the 3-4 GHz span

YES

Measure VCO supply voltage at C560

C501

= 2.8 V OK ?

YES

C52

YES

Synthesizer is ok

Wrong frequencies found

YES

Measure VCO control voltage at C505. Voltage = 4.8V?

VCO does not work or the control loop is open

C504

Replace VCO

Check C503, R501, R502,

Check R502, C503, C504

C504, C505

R501 and C502

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RM-14 RF Troubleshooting and Manual Tuning Nokia Customer Care

Tx Troubleshooting

Figure 3:Helgo/Synthesizer

Figure 4:PA/TX

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RM-14

TX850/900 GMSK t

Nokia Customer Care RF Troubleshooting and Manual Tuning

■ Tx 900 GMSK troubleshooting

Figure 5:TX 900 GMSK troubleshooting

TX 900 GMSK troubleshooting

Apply a 50 ohm load at the antenna connector of the jig. GSM900/ cha. 37 = 897.4 MHz, burst mode power level 10 Spectrum analyzer: RBW = 500 Khz and VBW = 500 kHz, center = 500 kHz and span = 20 MHz

Measure voltage of a) TXI at C529 and TXQ at C530, Txi and TXQ = 500 mVpp min. and 1.4 VDC during burst

Measure a) TXC = 800 mV during burst at R514 and b) TXP = 1.8 V during burst at J504 . Note: TXC voltage is a function of power level

roubleshooting

Measure modulator supply voltage VR2 = 2.7 V (C511, both terminals)

Measure RF level = -13 dBm at input of Z700 SAW filter C702

Measure RF level = -13 dBm at N700 PA input (R704 pin1)

Measure RF level = +10 dBm at N700 PA output TX_OUT_EGSM (Z800 pin1)

Measure N700 PA power detector DET = 850 mV during burst at R701.

Note: DET voltage is a function of power level

Measure N700 PA control voltage a) VPCTRL_G = 1.2 V during burst at R713 and N700 PA bias voltage. b) VTXB_G = 2.7V (C701). Note: VPCTRL_G voltage is a function of power level.

NOK

Check baseband.

Check N500 Helgo.

Check Z700 Tx SAW.

Measure N700 PA supply voltage VBAT at C705

Measure RF level = 20 dBm at antenna pad J124

Measure Z800 antenna switch control signal voltages a) VANT_1 = 2.7 V at C811

b) VANT_2 = 0 V at C809 c) VANT_3 = 2.7 V at C810

10 COMPANY CONFIDENTIAL ISSUE 1 11/04

RM-14 RF Troubleshooting and Manual Tuning Nokia Customer Care

■ Tx 1800/1900 GMSK troubleshooting

Figure 6:TX 1800/1900 GMSK troubleshooting

TX1800/1900 GMSK troubleshooting

Apply a 50 ohm load at the antenna connector of the jig. GSM1800 ch. 700 = 1747,8 MHz, burst mode power level 5 GSM1900 ch. 661 = 1880,0 MHz, burst mode power level 5 Spectrum analyzer RBW = 500 kHz and VBW = 500 kHz and span = 20 MHz

Measure voltage of a) TXI at C529 and TXQ at C530, Txi and TXQ = 500 mVpp min. and 1.4 VDC during burst

Measure a) TXC = 800 mV during burst at R514 and b) TXP = 1.8 V during burst at J504 .

Note: TXC voltage is a function of power level

Measure modulator supply voltage VR2 = 2.7 V at L505

Measure RF level = -15 dBm at input of T700 Tx balun C714

Measure RF level = -10 dBm at N700 PA input R707 pin1

Measure RF level = -3 dBm at N700 PA output TX_OUT_DCS (Z800)

NOK

Measure N700 PA power detector DET = 810 mV during burst at R701.

Note: DET voltage is a function of power level

Measure N700 PA control voltage a) VPCTRL_1800/1900 = 1.0 V during burst at R715 and N700 PA bias voltage

and N700 PA bias voltage b) VTXB_1800/1900 = 2.7 V (C709). Note: VPCTRL_1800/1900 voltage is a function of power level.

NOK

Check baseband.

Check N500 Helgo.

Check T700 Tx balun.

Measure N700 PA supply voltage VBAT at C705

Measure RF level = 2 dBm at antenna pad J124

Measure Z800 antenna switch control signal voltages a) VANT_1 = 0 V at C811

b) VANT_2 = 2.7 V at C809 c) VANT_3 = 2.7 V at C810

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Nokia Customer Care RF Troubleshooting and Manual Tuning

Rx Troubleshooting

Figure 7:Helgo/Synthesizer

Figure 8:PA/TX

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■ Rx 900 troubleshooting

Figure 9:RX 900 troubleshooting

RX 900 Troubleshooting

GSM900 ch. 37. Continuous Rx. Use AGC “gain step” 14

Apply a signal of 942.46771 MHz (+67.71 kHz offset) at -90 dBm to the antenna pad J124

Spectrum analyzer: RBW = 500 kHz, VBW = 500 kHz, center = 942 MHz and span = 20 MHz

Measure voltage of a) RXI (J512) b) RXQ (J513). RXI and RXQ = 800 mVpp and 1.35 VDC.

Note: DC level drops after a while. Change the signal level to -30 dBm

Measure RF level = -55 dBm at Z803 SAW filter input.

NOK

Measure Z800 antenna switch control signal voltages

a) VANT_1 = 0V (C811) b) VANT_2 = 0V (C809)

c) VANT_3 = 0V (C810).

Measure RF level = -55 dBm at Helgo input (C808, both terminals).

NOK

go to “Helgo/Synthesizer troubleshooting”

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Nokia Customer Care RF Troubleshooting and Manual Tuning

■ Rx 1800 troubleshooting

Figure 10:RX 1800 troubleshooting

RX 1800 Troubleshooting

GSM1800 ch. 700. Continuous Rx. Use AGC “gain step” 14

Apply a signal of 1842,86771 MHz (+67.71 kHz offset) at -90 dBm to the antenna pad J124

Spectrum analyzer: RBW = 500 kHz, VBW = 500 kHz, center = 1840 MHz and span = 20 MHz

Measure voltage of a) RXI (J512) b) RXQ (J513). RXI and RXQ = 500 mVpp and 1.35 VDC.

Note: DC level drops after a while. Change the signal level to -30 dBm

Measure RF level = -30 dBm at Z802 SAW filter input.

(Z800 antenna switch pin11)

NOK

Measure Z809 antenna switch control signal voltages

a) VANT_1 = 0V (C811) b) VANT_2 = 0V (C809)

c) VANT_3 = 0V (C810).

Measure RF level (C807, not assembled, both terminals).

at Helgo input

NOK

go to “Helgo/Synthesizer troubleshooting”

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