Nokia 5140 Service Manual 06 npl4_5 trouble

Nokia Customer Care

NPL-4/5 Series Transceivers

Troubleshooting Instructions

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Table of Contents

Page No

RF Troubleshooting.................................................................................................................................. 6

Introduction to RF troubleshooting ................................................................................................6

RF Key component placement ..........................................................................................................7

RF Test Points............................................................................................................................................ 8

Receiver ...................................................................................................................................................9

Transmitter ...........................................................................................................................................10

Synthesizer ...........................................................................................................................................10

RF in General.......................................................................................................................................... 11

RF Power Supply Configuration........................................................................................................ 13

Receiver Verification and Troubleshooting ................................................................................... 15

General instructions for RX troubleshooting ..............................................................................15

Measuring RX I/Q Signals using RSSI Reading....................................................................... 15

Measuring RX performance using SNR measurement ......................................................... 17

Measuring front-end power levels using spectrum analyzer............................................. 18

Measuring analogue RX I/Q signals using oscilloscope....................................................... 19

Fault finding chart of the receiver............................................................................................. 20

Rx signal paths ....................................................................................................................................24

Antenna switch (RX/TX switch) .................................................................................................. 24

Rx front-end..................................................................................................................................... 25

RX paths of RF ASIC....................................................................................................................... 26

Transmitter ............................................................................................................................................. 27

General instructions for transmitter troubleshooting .............................................................27

Transmitter troubleshooting ............................................................................................................27

Antenna switch (TX/RX switch) .................................................................................................. 27

GSM850 transmitter ..........................................................................................................................28

General instructions for GSM850 TX troubleshooting......................................................... 28

GMSK.................................................................................................................................................. 28

EDGE................................................................................................................................................... 29

Fault Finding Chart for GSM850 Transmitter......................................................................... 30

GMSK.................................................................................................................................................. 31

EDGE................................................................................................................................................... 32

GSM900 transmitter ..........................................................................................................................32

General instructions for GSM TX troubleshooting ................................................................ 32

GMSK.................................................................................................................................................. 32

EDGE................................................................................................................................................... 33

Fault finding chart for GSM900 transmitter .......................................................................... 34

GMSK.................................................................................................................................................. 35

EDGE................................................................................................................................................... 36

GSM1800 transmitter .......................................................................................................................36

General instructions for GSM1800 TX troubleshooting ...................................................... 36

GMSK.................................................................................................................................................. 36

EDGE................................................................................................................................................... 37

Fault finding chart for GSM1800 transmitter........................................................................ 38

GMSK.................................................................................................................................................. 39

EDGE................................................................................................................................................... 40

GSM1900 transmitter .......................................................................................................................40

General instructions for GSM1900 TX troubleshooting ...................................................... 40

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GMSK.................................................................................................................................................. 40

EDGE................................................................................................................................................... 41

Fault finding chart for GSM1900 transmitter........................................................................ 42

GMSK.................................................................................................................................................. 43

EDGE................................................................................................................................................... 44

Synthesizer ............................................................................................................................................. 45

Check synthesizer operation ...........................................................................................................45

Reference oscillator 26 MHz (VCTCXO) ........................................................................................46

Voltage Controlled Oscillator (VCO) ..............................................................................................47

Fault finding chart for PLL synthesizer ........................................................................................48

Pictures of synthesizer signals ........................................................................................................49

Frequency tables .................................................................................................................................51

GSM850............................................................................................................................................. 51

GSM900 (including EGSM900)................................................................................................... 52

GSM1800 .......................................................................................................................................... 53

GSM1900 .......................................................................................................................................... 55

DC Supply Current Check ................................................................................................................... 57

Baseband Troubleshooting................................................................................................................. 58

BB measurement points ...................................................................................................................58

Troubleshooting diagrams ................................................................................................................60

Phone is dead. .....................................................................................................................................61

Phone is jammed 1 .............................................................................................................................62

Phone is jammed 2 .............................................................................................................................63

Flash faults 1 .......................................................................................................................................64

Flash faults 2 .......................................................................................................................................65

SIM card faults ....................................................................................................................................66

Charger faults ......................................................................................................................................67

Display faults 1 ...................................................................................................................................68

Display faults 2 ...................................................................................................................................69

Audio fault1 .........................................................................................................................................70

Audio fault 2 .................................................................................................................

Audio fault 3 ........................................................................................................................................72

Keyboard faults 1 ...............................................................................................................................73

Keyboard faults 2 ...............................................................................................................................74

Keyboard faults 3 ...............................................................................................................................75

Keyboard faults 4 ...............................................................................................................................76

Keyboard faults 5 ...............................................................................................................................77

Accessory faults1 ................................................................................................................................78

Accessory faults 2 ..............................................................................................................................80

Flashlight faults ..................................................................................................................................82

Self tests ...............................................................................................................................................83

FCI troubleshooting ...........................................................................................................................84

IHF troubleshooting ...........................................................................................................................86

Compass Troubleshooting .................................................................................................................. 87

Calibration 1 ........................................................................................................................................88

Calibration 2 .................................................................................................................

Sensor problems 1 ..............................................................................................................................90

Start calibration ..................................................................................................................................91

.......................71

.......................89

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Magic troubleshooting ......................................................................................................................94

FM Radio Troubleshooting ................................................................................................................. 95

FM radio component layout ............................................................................................................95

FM radio troubleshooting diagram ................................................................................................97

List of Figures

Page No

Fig 1 Component placement 1................................................................................................................... 7

Fig 2 Picture of the Assembled PWB with Chambers.......................................................................... 8

Fig 3 Receiver Test Points............................................................................................................................ 9

Fig 4 Transmitter Test Points...................................................................................................................... 10

Fig 5 Synthesizer Test Points...................................................................................................................... 10

Fig 6 RF Block -Diagram .............................................................................................................................. 11

Fig 7 RF Power Supply Configuration ...................................................................................................... 12

Fig 8 RSSI Window ........................................................................................................................................ 16

Fig 9 Signal Measurement........................................................................................................................... 18

Fig 10 Signal Amplitudes............................................................................................................................. 19

Fig 11 RX IQ Signals...................................................................................................................................... 20

Fig 12 Receiver Fault Chart 1..................................................................................................................... 21

Fig 13 Receiver Fault Chart 2..................................................................................................................... 22

Fig 14 Receiver Fault Chart 3, 4, 5 .......................................................................................................... 22

Fig 15 Receiver Fault Chart 6..................................................................................................................... 23

Fig 16 Receiver Fault Chart 7..................................................................................................................... 23

Fig 17 Receiver Fault Chart 8..................................................................................................................... 24

Fig 18 Receiver Fault Chart 9..................................................................................................................... 24

Fig 19 Block Diagram of Antenna Switch: Left Input Port (Antenna) and Right Output Ports Rx/

Tx........................................................................................................................................................................... 25

Fig 20 RF Controls.......................................................................................................................................... 29

Fig 21 RF Controls.......................................................................................................................................... 30

Fig 22 Band Selection................................................................................................................................... 33

Fig 23 RF Control Values.............................................................................................................................. 34

Fig 24 RF Control Values.....................................................................................................

Fig 25 RF Control Values.............................................................................................................................. 38

Fig 26 RF Control Values.............................................................................................................................. 41

Fig 27 RF Control Values.............................................................................................................................. 42

Fig 28 Typical Feature Tuning Curve for the Matshushita VCO........................................................ 46

Fig 29 26 Mhz at G501 Pin Out................................................................................................................. 49

Fig 30 26 MHz RFCLK at R420/C420 ....................................................................................................... 49

Fig 31 VCO Output, 1800 Band, RX on, Continuous Output ............................................................. 50

Fig 32 DC Power Supply Diagram.............................................................................................................. 57

Fig 33 NPL-4/5 BB Measurement Points, Top ...................................................................................... 58

Fig 34 NPL-4/5 BB Measurement Points, Bottom................................................................................ 59

Fig 35 MBUS.................................................................................................................................................... 79

Fig 36 ACI Diagram ...................................................................................................................................... 81

Fig 37 Testpoints............................................................................................................................................ 92

Fig 38 Component placement ................................................................................................................... 95

Fig 39 Trace layout....................................................................................................................................... 96

Fig 40 FM radio block layout.................................................................................................

......................... 37

..................... 96

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Fig 41 FM radio troubleshooting diagram.............................................................................................. 98

Fig 42 Oscilloscope screen shot, Audio output ..................................................................................... 99

Fig 43 FM radio clock from test point J359, 32 kHz frequency clock signal, when radio is on. 100

Fig 44 FM frequency from FM radio pin 37, the other end of L358, with FM test signal........ 100

Fig 45 VCO frequency from FM radio pins 3 and 4, the other ends of V356 and V357, with FM

test signal ........................................................................................................................................................... 100

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RF Troubleshooting

Introduction to RF troubleshooting

Measurements should be done using Spectrum analyzer with high-frequency highimpedance passive probe (LO-/reference frequencies and RF power levels) and Oscilloscope with a 10:1 probe (DC-voltages and low frequency signals)

The RF-section is built around one RF-ASIC (Helgo N500). For easier troubleshooting, this RF troubleshooting document is divided in to sections.

Before changing Helgo, please check following things: Supply voltages are OK and serial communication is coming from baseband to Helgo.

Please note that the grounding of the PA module is directly below PA-module so it is difficult to check or change. Most RF semiconductors are static discharge sensitive! So ESD protection must be taken care of during repair (ground straps and ESD soldering irons). Helgo and PA are moisture sensitive so parts must be pre-baked prior to soldering.

Apart from key components described in this document here are a lot of discrete components (resistors, inductors and capacitors) which troubleshooting is done by checking if soldering of the component is done properly (for factory repairs checking if it is missing from PWB). Capacitor can be checked for shortening and resistors for value by means of an ohmmeter, but be aware in-circuit measurements should be evaluated carefully.

Please be aware that all measured voltages or RF levels in this document are rough figures. Especially RF levels varies due to different measuring equipment or different grounding of the used probe. When using RF probe usually a good way is to use metallic tweezers to connect probe ground to PWB ground as close to measurement point as possible.

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RF Key component placement

Figure 1: Component placement 1

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RF Test Points

The RF power supplies are generated in the UEM and can be measured either in the Small Signal Chamber or in the Baseband Chamber. On the drawings below small points show the locations of the test points.

Figure 2: Picture of the Assembled PWB with Chambers

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Receiver

Figure 3: Receiver Test Points

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Transmitter

Figure 4: Transmitter Test Points

Synthesizer

Figure 5: Synthesizer Test Points

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RF in General

Figure 6: RF Block -Diagram

RF block diagram consisting of:

• RF front-end module

• Power amplifier module

•RF ASIC

• VCTCXO module

• VCO module

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The RF front-end is a triple-band direct conversion transceiver. Using direct conversion, no intermediate frequencies are used for up- or down-conversion.

Figure 7: RF Power Supply Configuration

GSM: 869- 894 MHz 925-960 MHz

DCS: 1805-1880 MHz PCS: 1930-1990 MHz

Helgo

I-signal Q-signal

DCS: 1710-1785 MHz

PCS: 1850-1910 MHz

GSM: 824-849 MHz 880-915 MHz

f/4

f/2

32963980 MHz

f/2

PLL

Buffer

26 MHz VCTCXO

AFC

VCTCXO 26 MHz

I-signal Q-signal

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RF Power Supply Configuration

General Specifications of Transceiver

Parameter Unit

Cellular System GSM850/900, GSM1800, GSM1900

Modulation schemes GMSK, 8-PSK

RX Frequency Band GSM850:824 … 849 MHz

GSM900:925 … 960 MHz GSM1800:1805 ... 1880 MHz GSM1900:1930 … 1990 MHz

TX Frequency Band GSM850:869 … 894 MHz

GSM900:880 … 915 MHz GSM1800:1710 ... 1785 MHz GSM1900:1850 … 1910 MHz

Output Power GMSK GSM850:+5 … +33 dBm (3.2 mW … 2 W)

GSM900:+5 … +33 dBm (3.2 mW … 2 W) GSM1800:+0 … +30 dBm (1.0 mW … 1 W) GSM1900:+0 … +30 dBm (1.0 mW … 1 W)

Output Power 8-PSK GSM850:+5 … 27 dBm (3.2 mW … 0.5 W)

GSM900:+5 … 27 dBm (3.2 mW … 0.5 W) GSM1800:+0 … 26 dBm (1.0 mW … 0.4 W) GSM1900:+0 … 26 dBm (1.0 mW … 0.4 W)

Duplex Spacing GSM850:45 MHz

GSM 900:45 MHz GSM 1800:95 MHz GSM 1900:80 MHz

Number of RF Channels GSM 850:124

GSM 900:174 GSM 1800:374 GSM1900:299

Channel Spacing 200 kHz (each band)

Number of TX Power Levels GMSK

EGSM:15 GSM 900:15 GSM 1800:16 GSM 1900:16

Number of TX Power Levels 8-PSK

Sensitivity, static channel (+25°C)

GSM 850:12 GSM 900:12 GSM 1800:14 GSM 1900:14

EGSM:-102 dBm GSM 900:-102 dBm GSM 1800:-102 dBm GSM 1900:-102 dBm

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Frequency Error, static channel < 0.1 ppm

RMS Phase Error < 5.0 °

Peak Phase Error < 20.0 °

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Receiver Verification and Troubleshooting

General instructions for RX troubleshooting

Connect the phone to a PC, which has Phoenix Service Software and a dongle installed, using either

• Repair jig and DAU-9S (RS232) cable or

• DAU-9T cable (RS232) or

• DKU-5 cable (USB)

Connect the phone to a power supply (DC voltage: 4.0V, max. current: 3A) and an RF signal generator. Switch the phone on.

Start Phoenix Service Software and open FBUS connection.

- Select → Scan Product (Ctrl-R)

Wait until phone information (NPL-4 or NPL-5) is shown in the lower right corner of the screen.

Follow the instructions below.

Measuring RX I/Q Signals using RSSI Reading

- Start Phoenix Service Software and open FBUS connection.

- Select → Scan Product (Ctrl-R)

Wait until phone information is shown in the lower right corner of the screen.

- Set operating mode to local mode

- Select → Testing → RF Controls

- Select → Band → GSM 850 or GSM 900 or GSM1800 or GSM1900

Active unit → RX

Operation mode → Burst

RX/TX Channel → 190 or 37 or 700 or 661

- Select → Testing → RSSI reading

In the RSSI Reading window the “measuring mode” shall be set on Sum vector and the “reading mode” on Continuous.

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The set up should now look like this:

Figure 8: RSSI Window

- Make the following settings on your signal generator:

Frequencies:

• GSM 850: 869.26771 MHz (channel 190 + 67.710 kHz offset)

• GSM 900: 942.46771 MHz (channel 37 + 67.710 kHz offset)

• GSM 1800: 1842.86771 MHz (channel 700 + 67.710 kHz offset)

• GSM 1900: 1960.06771 MHz (channel 661 + 67.710 kHz offset)

2. RF power level:

– 60 dBm @ the antenna connector of the phone/ test jig

(Remember to compensate for the cable and jig attenuation).

- Click on “Read now” in RSSI reading.

The resulting RSSI level shall be – 60 dBm +/– 0.5 dB in each band.

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Measuring RX performance using SNR measurement

- Start Phoenix Service Software and open FBUS connection.

- Select → Scan Product (Ctrl-R)

Wait until phone information is shown in the lower right corner of the screen.

- Set operating mode to “local mode”.

- Select → Testing → RF Controls

- Select → Band → GSM 850 or GSM 900 or GSM1800 or GSM1900

Active unit → RX

Operation mode →Burst

RX/TX Channel → 190 or 37 or 700 or 661

- Select → Testing → SNR Measurement

- Select → Measuring mode → Fast SNR (Radio Button)

- Press → Start

The window “Signal Measurement” pops up informing on frequency and power level of the signal generator to be set.

- Press “ok” and the window will close.

- Read the SNR results.

The values should exceed:

• GSM 850: > 20 dB

• GSM 900: > 20 dB

• GSM 1800: > 18 dB

• GSM 1900: > 18 dB

The set up should now look like this:

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Figure 9: Signal Measurement

- Choose the remaining GSM bands and measure accordingly the procedure described above.

Measuring front-end power levels using spectrum analyzer

Spectrum Analyzer (SA) level values depend on the probe type and shall be verified by a properly working phone sample.

- Start Phoenix Service Software and open FBUS connection.

- Select → Scan Product (Ctrl-R)

Wait until phone information is shown in the lower right corner of the screen.

- Set operating mode to “local mode”

- Select → Testing → RF Controls

- Select → Band → GSM850 or GSM 900 or GSM1800 or GSM1900

Active unit → RX

Operation mode → Continuous

RX/TX Channel → 190 or 37 or 700 or 661

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Measuring analogue RX I/Q signals using oscilloscope

Measuring with an oscilloscope on “RXIINN”, (R421) or “RXQINN”, (R423) is recommended only if RSSI reading does not provide enough information. Input level = -60dBm.

- Start Phoenix Service Software and open FBUS connection.

- Select → Scan Product (Ctrl-R)

Wait until phone information is shown in the lower right corner of the screen.

- Set operating mode to “local mode”

- Select → Testing → RF Controls

Wait until the RF Controls window is popped up.

- Select → Band →GSM 850 or GSM 900 or GSM1800 or GSM1900

Active unit → RX

Operation mode → continuous

RX/TX Channel → 190 or 37 or 700 or 661

AGC → 12

Following diagram should be displayed on an oscilloscope' s screen if the GSM 900 receiver is working properly:

Figure 10: Signal Amplitudes

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Correct signal amplitudes approximately

GSM850/900: ~140-150mVpp

GSM1800/1900: ~130-150mVpp

Signal frequency 67.7kHz

Figure 11: RX IQ Signals

RX I/Q, phase difference 90 degrees between signals.

RX I/Q-signals measured from R423 (Q-signal), R421 (I-signal) simultaneously.

Used channel 37, input signal 942.467 MHz, level –60 dBm at antenna port, AGC setting

12.

Phase difference should be 90 degrees between RX I/Q-signals at all bands.

Fault finding chart of the receiver

During fault finding, the calibration procedure is used to find out, whether all bands are affected (error in common part of the Rx chain) or only one band (error in a Rx part of the failed band). Take care not to save calibration values to the phone memory, which are out of limits. Find the error first and repair it.

When a defective phone has been calibrated, a possible error in RX front-end might be masked. In that case one can get a reasonable RSSI reading, although the front-end shows excessive losses. If it is not sure that incorrect re-calibration has been made, following steps shall be done:

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- Check if AGC calibration is within limits

- Check if SNR reading is OK.

- Use an Oscilloscope to check levels of “RXI” and “RXQ”.

The RF ASIC generates only single ended I and Q signals (RXI, RXQ). As the A/D converter in UEM requires two differential signals, an artificial mid voltage is generated from VrefRF02.

The BB part is used to measure those signals by means of RSSI reading. This works only if correct calibration has been carried out in production.

RSSIreading [dBm] = 20log(UBB/U

LSB

) - AGC

calibrated

If both RX and TX path seem to be faulty it has to be checked if the synthesizer is working.

Figure 12: Receiver Fault Chart 1

Phoenix:

Phone: local mode

Open

Signal Gener a t o r:

Phoenix:

Open Check RSSI Level = -80dBm

Make sure that

Synthesizer is working

Yes

All 3 bands

RF Controls

Active Unit: Rx Op. Mode: Burst Rx/Tx channel: default (mid)

Level: –80dBm Frequency: calculated from Phoenix + 67.71kHz

RSSI reading

Yes Next band No

see

Synthesizer Fault Finding Tree

Selected band is working and calibrated.

re all 3 bands measured?

Receiver Fault Chart 1.

Execute Rx Calibration in select ed band

re calibration results within limits?

re all 3 bands measured?

Yes

Rx chain is functional

and calibrated

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Figure 13: Receiver Fault Chart 2

Are all 3 bands defective?

Yes

Oscilloscope:

Check supply voltages of RF ASIC: VR4 = 2.8V

Oscilloscope:

Check supply voltages of RF ASIC: VR6 = 2.8V

Oscilloscope:

Check reference voltages of RF part: VrefRF01 = 1.4V

Continue with single band fault finding.

Receiver Fault Chart 2.

Figure 14: Receiver Fault Chart 3, 4, 5

Yes

Check supply filter components (C297, C554) and UEM

Check supply filter components (C225, C555) and UEM

Check supply filter components (R525, C549)

Receiver Fault Chart 3.

Receiver Fault Chart 4.

Yes

Oscilloscope:

Check reference voltages of RF part: VrefRF02 = 1.4V

Yes

Phoenix:

Phone: local mode

RF Controls

Active Unit: Rx Op. Mode: Rx/Tx channel: default (mid) AGC: 12

Signal Generator:

Level: –55dBm

Frequency: calculated from Phoenix no offset

Spectrum Anal yzer: 1)

Check Rx/Tx Switch (Diplexer)

Depending on selected band, check

GSM850/900 output Rx1 GSM1800 output Rx2 GSM1900 output Rx3

Level at Z809 output > -75dBm

Continuous

Yes

Ye s

Check supply filter components (R421, R423, C421, C422) and UEM

Receiver Fault Chart 5.

Change Z809

Note! 1) RF levels are dependent on RF probe

Note 1): RF levels are dependent on RF probe and have to be validated

and have to be validated with a known good

with a known good sample.

sample.

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Figure 15: Receiver Fault Chart 6

Oscilloscope:

RX IQ levels ok (RXI, RXQ)?

Yes

Change RF ASIC (Helgo)

Receiver Fault Chart 6.

Oscilloscope:

RF-BB serial interface ok?

Select faulty band in Phoenix and continue measurements on dedicated Rx part.

Phoenix:

SNR Measurement

open

Meas. Mode: Fast SNR

Measure

Press

Signal Generator:

Level: –92dBm

Fre

uency: calculated from Phoenix

Phoenix: SNR measurement ok?

(SNR > 18.37dB)

Yes

Check UPP

Change RF ASIC (Helgo)

Figure 16: Receiver Fault Chart 7

Single band fault finding

BB error:

Yes

Front end is ok.

Phoenix:

Phone: local mode

RF Controls

Active Unit: Rx Op. Mode: Rx/Tx channel: default (mid) AGC: 12

Signal Generator:

Level: –55dBm

Frequency: calculated from Phoenix no offset

Continuous

Continue with Rx Fault Chart 6.

Receiver Fault Chart 7.

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Figure 17: Receiver Fault Chart 8

Phoenix:

Phone: local mode

RF Controls

Active Uni t: Rx Op. Mode: Rx/Tx channel: defaul t ( mid) AGC: 12

Signal Generator:

Level: –55dBm

Frequency: calculated from Phoenix (no offset)

Spectrum Analyzer: 1)

Center Freq: calculated from Phoenix

RBW 20kHz

Check Rx SAW filter of selected band:

GSM850/900 Z808

output both lines > -80dBm GSM1800 Z807 output both lines > -80dBm GSM1900 Z806 single output > -74dBm

Continuous

Yes

Change Rx SAW (Z806, Z807, Z808)

depending on selected band

Note 1):

Note! 1) RF levels are dependent on RF probe

RF levels are dependent on RF probe and have to be valid ated

and have to validated with a known good sample.

with a known good sample.

Receiver Fault Chart 8.

If selected band = GSM1900

Spectrum Analyzer:

Check external LNA V802: Output signal pin 3 > - 56dBm

Spectrum Analyzer: 1)

Check balun T801: Both output signals at pin 3+4 > - 62dBm

RF ASIC N500 seems to be defective. Exchange N500.

Yes

Figure 18: Receiver Fault Chart 9

Change V802

Oscilloscope:

Check voltages for V802:

Voltage at C827 = 2.6V Volta

e at C801 = 0V

Yes

Note 1):

Note! 1) RF levels are dependent on RF probe

RF levels are dependent on RF probe and have to be validated

and have to validated with a known good sample.

with a known good sample.

Receiver Fault Chart 9.

Check supply filter components around V802 and RF ASIC N500

Change T801

Rx signal paths

Antenna switch (RX/TX switch)

RF signal is fed directly from the antenna-pad (J908) to the antenna switch (Z809).

This switch has the function of a diplexer, which consists of two combined paths (low pass/high pass filter combination), a GSM850/900 and a GSM1800/1900 path. The GSM 850/900 input signals pass the switch to the Rx1 output. Via a switch the GSM 1800 input signals pass to Rx2 output and GSM 1900 to Rx3 output, depending on the control

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signal VANT3=1, whereas VANT1=VANT2=0.

• Signal paths from the antenna switch to the band filters: GSM 850/900:RX1 Æ GSM850 SAW filter (Z808) or

Æ GSM900 SAW filter (Z808)

• GSM1800: RX2 Æ GSM1800 SAW filter (Z807)

• GSM1900: RX3 Æ GSM1900 SAW filter (Z806)

The antenna switch has following typical insertion losses in Rx-mode from its input to output ports:

• GSM 850/900: 1.3 dB

• GSM 1800: 1.6 dB

• GSM 1900: 1.6 dB

Figure 19: Block Diagram of Antenna Switch: Left Input Port (Antenna) and Right Output Ports Rx/Tx

EGSM

LPF

HPF

LPF

GSM1800 GSM1900

LPF

Rx front-end

The RX front-end includes three SAW filters for GSM 850 [US-variant] or GSM 900 [EUvariant] (Z808), and for both variants GSM1800 (Z807), and GSM1900 (Z806). GSM 850/ 900 and GSM 1800 filters are matched to the corresponding LNA inputs of the RF ASIC (N500) with differential matching network (LC-type). For GSM 1900 an external LNA (V802) improves the noise figure of the receiver. For conversion of the unbalanced output port to the balances input port of the RF ASIC the BALUN (T801) is applied, followed by a differential matching network (LC-type). The SAW filters provide the wanted out-ofband blocking immunity. They have one single-ended (unbalanced) input port and two balanced output ports each.

The SAW filters have approximately 2.5 to 3.2 dB insertion losses. The LNA for the GSM 1900 band provides a gain of approximately 17 to 20 dB.

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RX paths of RF ASIC

The balanced GSM 850/900 and GSM 1800 RX signals are amplified by one integrated LNA for each band and the subsequent pre-gain stages. The GSM 1900 signal is fed to the pre-gain stage also used for the GSM 1800 signal. After amplification the RX signals are down-converted.

The RX paths of the RF ASIC consist of following sub units:

• Separate LNAs for each of the bands: GSM 850/900, and GSM1800.

• Two PRE-GAIN amplifiers, one for GSM 850/900 and one for GSM1800 and GSM1900.

• Two passive I/Q mixers (MIX), one for GSM 850/900 and one for GSM1800 and GSM1900.

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Transmitter

General instructions for transmitter troubleshooting

Connect the phone to a PC, which has Phoenix Service Software and a dongle installed, using either

• Repair jig and DAU-9S (RS232) cable or

• DAU-9T cable (RS232) or

• DKU-5 cable (USB).

Connect the phone to a power supply (DC voltage of 3.9V) and switch the phone on. The value of the DC voltage of 3.9V at the phone battery connector is crucial.

Attention: When repairing or tunning transmitter use external DC supply with at least 3A current capability.

Connect an RF cable between the test jig and the measurement equipment (GSM test equipment, power meter, spectrum analyzer, or similar).

Make use of an adequate attenuator at the input of your measurement equipment (10dB to 20dB are recommended for a spectrum analyzer or a power meter). Additionally, a DC block is recommended. Assure not to overload or destroy the equipment.

Start Phoenix Service Software and open FBUS connection:

Select->Scan Product->Ctrl-R

and wait until phone information is shown in the lower right corner of the screen.

Follow the instructions in the chapters below.

Transmitter troubleshooting

Antenna switch (TX/RX switch)

The antenna switch operates as a diplexer for the RX and TX signals. Moreover, it suppresses the TX harmonics generated by the PA. The antenna switch is a controlled by the RF ASIC using the control signals VANT1, VANT2 and VANT3.

The table below shows the possible different switching states.

Company confidential NPL-4/5

Nokia Customer Care Troubleshooting Instructions

Table 1: Switching States

VANT2

VC1

[Volt]

0 0 0 X

0 0 2.7 X

0 2.7 0 X

2.7 2.7 0 X

VANT3

VC2

[Volt]

To switch the TX -GSM 1800/1900 path both signals VANT2 and VANT3 have to be activated. This increases the isolation from the TX-GSM 1800/1900 path to the RX-GSM 1800 path and reduces the feed back of RF-power to the RF ASIC.

GSM850 transmitter

GSM850 chapture is valid only for the NPL-4 (US variant). Start the preparations as described in chapter General instruction for the transmitter troubleshooting.

VANT1

VC3

[Volt]

Rx1

GSM

900

850/

Rx2

GSM

1800

Rx3

GSM

1900

TX_IN_E GSM

Tx1

GSM

850/

900

TX_IN_D CS

Tx2

GSM

1800/1900

General instructions for GSM850 TX troubleshooting

GMSK

Select operating mode to “local mode”:

Select->Testing->RF Controls

In the popped up window:

Select->Band->GSM 850

-Active unit->TX

-Operation mode->Burst

-RX/TX Channel->190

-TX Power Level->10

-TX Data Type->Random

The Phoenix window should now look like this:

NPL-4/5 Company confidential

Troubleshooting Instructions Nokia Customer Care

Figure 20: RF Controls

EDGE

Now the measurement setup, which has been built according to the Check synthesizer Operation-chapter, should detect the following output signal of the phone.

= +23dBm @ 836.6 MHz

out

If this is not the case, then go to the chapter GMSK for the troubleshooting.

Start the preparations as described in chapter Check synthesizer Operation.

Select operation mode to the “local”.

Select->Testing -> RF control

In the popup window common values:

Active unit:->TX

Band: ->850

Operation mode: ->Burst

RX/TX Channel:->190

In the popup window TX control values:

EDGE:->ON

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