09_RH79_SM_rf

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Issue 1 02/2006 Company Confidential © 2006 Nokia Corporation

Nokia Customer Care

1255 (RH-79)

Mobile Terminal

RF Description andTroubleshooting

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1255 (RH-79) RF Description and Troubleshooting

Page 2 © 2006 Nokia Corporation Company Confidential Issue 1 02/2006

Contents Page

Component Layout ................................................................................................... 3 Tx Troubleshooting................................................................................................... 5

Tx system block diagram...................................................................................5 Tx introduction...................................................................................................6 Main TX component ..........................................................................................6 FTM setup for TX troubleshooting .....................................................................7 TX DC Test Points .............................................................................................8 Tx RF Test Points ..............................................................................................9 Tx DC Test Points............................................................................................10 Tx path troubleshooting................................................................................... 11

Rx Troubleshooting ................................................................................................ 12 Rx system block diagram ................................................................................12

Rx introduction ................................................................................................13

FTM setup for RX troubleshooting...................................................................13 Cell Receiver Check from RF to IQ .................................................................14 Receiver DC Test Points.................................................................................16 Receiver RF Test Points .................................................................................17 Rx path troubleshooting...................................................................................18

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1255 (RH-79) Nokia Customer Care RF Description and Troubleshooting

Issue 1 02/2006 © 2006 Nokia Corporation Company Confidential Page 3

Component Layout

Figure 1 and Figure 2 show the main components of the 1255 mobile terminal.

Figure 1: Component layout (Top)

RF connector

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Figure 2: Component layout (Bottom)

Cell Duplexer

Power Amplifier

Tx Saw filter

RF Transmitter

32.768KHz Crystal

Power management IC

19.2MHz TCXO

Rx Saw filter

RF receiver

RF Antenna feed point

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Nokia Customer Care R

Issue 1 02/2006 © 2006 Nokia Corporation Company Confidential

Tx Troubleshooting Tx system block diagram

Figure 3: Tx system block diagram

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Page 6 © 2006 Nokia Corporation Company Confidential

Tx introduction

The RFT6122 (Figure 3) provides the Zero-IF transmit signal path for Cellular-CDMA transmission. For to band classes 0 and 3 as defined by the cdma2000 standard, with mobile station transmitters operatin

transmit signal path includes baseband amplifiers, quadrature upconversion, gain control RF amplificatiThe driver amplifier output is routed to the final stages of the transmit chain – power amplifier, isolator, d

Main TX component

Figure 4: Tx components

TX IC

TX Saw filter

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FTM setup for TX troubleshooting

Put PWB on the module jig. Use the following steps to configure FTM for RFtroubleshooting.

1. Connect RF test connector to a spectrum.2. Set SW1 to “FTM mode” in Module Jig.3. Connect the mobile terminal to a PC via the Module Jig, and connect a

power supply.4. Open CCS RF Tools software.5. The FTM dialog box appears.6. “Select COM port” to appropriate one7. Set “Connect Phone”.8. Set “Set FTM”.9. Set “Set Band” to “CDMA800”.

10. Set “Set Channel “to Channel “384”.11. Set “Set Pa Range R1” to “on”

12. Set “Set TX waveform” to “CDMA”13. Set “Set TX on/off” to “on”.14. Set “Set TX AGC” to “120”.

Figure 5: FTM dialog box

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TX DC Test Points

Figure 6: Tx DC test point

Table 1 shows the Tx DC test points shown in Figure 6.

Table 1: Tx DC Test Points

Test Point Description Value

1 PA_ON 3.08V for PA turning on, 0V for turning off

2 PA_R1 2.16V for high gain mode,1.6V for low gain mode

3 LOCK_DET 3.08V for Lock, 0 V for unlock

4 TX_AGC 1.92V for 5dBm, 2.16V for 15dBm, 2.4V for 25dBm.

5 Tx IQ in 0.8 V With oscilloscope: 500 mV p-p

6 DAC_REF 2.0 V

7 VREG_MSMP 2.9V8 VREG_RFTX 2.6V

7 8

5

3

1 4

2

6

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4

3

21

5

Tx RF Test Points

Figure 7: Tx RF Test Points

Table 2 shows the test points shown in Figure 7.

Table 2: Tx RF Test Points

Test Point Description Value1 RFT6122 output 4dBm

2 PA input 2dBm

3 PA output 28dBm

4 RF connector 24dBm

5 UHF LO 0dBm at 1763.04MHz

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Tx DC Test Points

Figure 8: Bottom side Tx DC test points

Table 3 shows the Tx DC test points shown in Figure 8.

TestPoint

Description Value RF Supply Lines Resistance to Ground

1 VREG_MSMP,c705 2.9V >11kΩ to ground U700,U900,U801,U602

2 VPH_PWR,c700 3.2~4.2V >550kΩ to ground U700,U7

3 VREG_MSMC,c706 2.6V >45kΩ to ground U700,U401

4 VREG_MSMA,c708 2.6V >120kΩ

to ground U700,U4015 VEXT_DC,r710 3.2~5.7V ~9.3kΩ to ground Q700

6 VREG_TCXO,c723 2.85V >450kΩ to ground U700

7 VREG_RFRX,r715 2.6V >350kΩ to ground U700,U900,U801

8 VREG_RFTX,c709 2.6V >450kΩ to ground U700,U900,U801

Table 3: Tx DC Test Points and RF Supply Line Resistance to Ground

*Note: Always measure resistance measure resistance with the phone powered off

32

41

8765

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Tx pathFaults

Measure DC testpoints at Table 1. Is

it OK?NO Check PM6610, MSM6000

YES

Measure Tx RF testpoints 6

at Table 2. Is it OK

NO Change RFT6122

YES

Reheat solder joints of C920, FL600, C619, U7

YES



NO Rehear solderjoints of R903,C911

Measure Tx RF test

points 2at Table 2. Is it OK

NO

NO Reheat solderjoints of U7

YES



YES

Reheat solder joints of F600, S600Measure Tx RF testpoints 4


NO

NO Change U7

NO Reheat solder joints of PM6610

YES

Check Antenna Module

If RF Antenna feed point padobstructed, clean the pad. Connect

System Simulator to MS antenna. Is itOK

NO

Tx path troubleshooting

Note: • MSM6000 is underfilled and can not be replaced.• Memory IC is underfilled and can not be replaced.

• The shield case can not be reused after removal.• After using the heatgun, the domesheet needs to be replaced.

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Page 12 © 2006 Nokia Corporation Company Confidential

Rx Troubleshooting Rx system block diagram

Figure 9: Rx DC troubleshooting test points

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Rx introduction

The RFR6122 IC (Figure 9) provides the Zero-IF receiver signal path for Cellular-CDMA reception. For this chipset, Cellular-CDMA refers to band classes0 and 3 as defined by the cdma2000 standard, with mobile station receiversoperating between 832 and 894 MHz. The Rx signal path includes the LNA,quadrature downconversion, and baseband functions.The Cellular-CDMA receive signal is routed from the antenna to the RFR6122 ICvia the duplexer. The analog baseband outputs interface with one of Qualcomm’sMobile Station MSM6000 devices that also provide status and control signaling.Integrated RX LO circuits, ideally supplemented by the RFT6122 transmitter IC,provide frequency plan flexibility and further reduce PCB parts count.

FTM setup for RX troubleshooting

Put PWB on the module jig. Use the following steps to configure FTM for RF

troubleshooting.1. Connect RF test connector to a spectrum.2. Set SW1 to “FTM mode” in Module Jig.3. Connect the mobile terminal to a PC via the Module Jig, and connect a

power supply.4. Open CCS Service Software and run RF Tools function.5. The FTM dialog box appears.6. “Select COM port” to appropriate one.7. Set “Connect Phone”.8. Set “Set FTM “.9. Set “RF Mode” to “CDMA800”.

10. Set “Set Channel “to Channel “384”.

11. Set “Set LNA Range” to whatever needed.

Figure 10: FTM dialog box

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Cell Receiver Check from RF to IQ

Use the following values to check the CDMA Cell Rx functionality from RF to IQoutput.

1. Start FTM in Local Mode with only the Rx path turned on and setLNA_GAIN_STATE=0.

2. Inject a –75 dBm CW signal of 881.82 MHz (i.e. 300 kHz offset from 881.52MHz or 10 channels away).

3. Measure a 300 kHz tuning on the analyzer. You should see a typical -52 dBm IQtuning for CDMA Cell.

Figure 11: Receiver IQ level on CDMA Cell band

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Figure 12 shows the Cell spectrum with an inject tone at -75 dBm, as well as the IQoutput test points. Note that DC is present on the IQ output test points. All testpoints should be approximately equal.

Figure 12: Cell spectrum (left) and IQ output test points (right)

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Receiver DC Test Points

Figure 13: Rx DC troubleshooting test points

Table 4 includes the descriptions and values for Rx DC troubleshooting test points

shown in Figure 13.

Test Point Description Value1 VREG_MSMP ,r806 2.9V

2 VREG_RFRX,r801 2.6V

3 LNA BIAS,L807 2.6V

Table 4: Rx DC Test Points

3

1

2

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Receiver RF Test Points

For the test points in Figure 14, an external signal source of –25 dBm was injectedto the RF input. Set LNA GAIN STATE = 3 .The signal was then traced throughoutthe receiver chains. An CMU200 call box is recommended. (Open non-signalingmode, press the SG soft button, and then select CW.) Inject a continuous wave(CW) for Cell (881.52MHz) at a fixed –25 dBm power level. Measurements weretaken with the RF Probe. Signal levels are approximate, and the accuracy may be+/- 2 dB or more depending on the probe position and grounding.

Figure 14: Receiver RF troubleshooting test points

Table 5 includes the descriptions and values for Rx RF troubleshooting test pointsshown in Figure 14.

Test Point Description Value

1 LNA IN -28dBm

2 RX SAW INPUT -48dBm

3 RX SAW OUTPUT -51dBm

Table 5: Rx RF Test Points

1

2

3

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Rx path troubleshooting

Note: • MSM6000 is underfilled and can not be replaced.

• Memory IC is underfilled and can not be replaced.• The Shielding Case Assy can not be reused after removal.• After using the heatgun, the domesheet needs to be replaced.

Rx pathFaults

Measure DC testpoints at Table 4. Is

it OK?NO

YES

Measure Rx RF test


NO

Reheat solder jointsof L804, C814 and

RFR6122

YES

Reheat solder joints

of U800

YES

Measure Rx RF testpoints 2


NO Reheat solder jointsof C813, L803

Measure Rx RF test


NO

NO Change RFR6122

Check PM6610 NOReheat solder joints

of PM6610

Check Antenna ModuleConnect System Simulator toMS antenna.

NO

YES

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