Nokia 6088, RM-218 Service Manual

Nokia Customer Care

6088 (RM-218)

Mobile Terminal

RF Description and

Troubleshooting

6088 (RM-218)

Nokia Customer Care RF Description and Troubleshooting

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

Main RX component ........................................................................................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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Nokia Customer Care RF Description and Troubleshooting

Component Layout

Figure 1 shows the main components of the 6088 mobile terminal.

RFAntenna

Direction Coupler

Power Amplifier

Tx Saw filter

RF Transmitter

Power Detector

Cell Duplexer

RF Receiver

Rx Saw filter

Power Mana

ement IC

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Nokia Customer Care RF Description and Troubleshooting

RF Connector

132.768KHz stal

Cr

19.2MHz TCXO

Figure 1: Component layout

6088 (RM-218)

Nokia Customer Care RF Description and Troubleshooting

Tx Troubleshooting

Tx system block diagram

Figure 2: Tx system block diagram

6088 (RM-218)

Nokia Customer Care RF Description and Troubleshooting

Tx introduction

The RFT6122 (Figure 2) provides the Zero-IF transmit signal path for Cellular-CDMA transmission. For this chipset, Cellular-CDMA refers to band classes 0 and 3 as defined by the cdma2000 standard, with mobile station transmitters operating between 824 and 925 MHz. The transmit signal path includes baseband amplifiers, quadrature upconversion, gain control RF amplification, and an output driver amplifier. The driver amplifier output is routed to the final stages of the transmit chain – power amplifier, isolator, duplexer, and antenna.

Main TX component

Power Amplifier

TX Saw filter

Direction coupler

Cell Duplexer

TX IC

Figure 3: Tx components

Power detector

ntial Page 6

6088 (RM-218)

Nokia Customer Care RF Description and Troubleshooting

FTM setup for TX troubleshooting

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

1. Select “FTM mode” in Module Jig

2. Connect RF connector to a spectrum by using CA-89RS RF Test Cable

3. Connect 6088 mobile terminal to a PC via Module Jig, and connect power supply to Module Jig

4. Open RF Tools software in 6088 CCS Level 3 service software

5. The FTM dialog box appears

6. Set COM port to appropriate one in “Select COM port”

7. 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 “100”

Figure 4: FTM dialog box

6088 (RM-218)

Nokia Customer Care RF Description and Troubleshooting

TX DC Test Points

6

1

3

2

4

5

U631pin8

8

Figure 5: Tx DC test point

Table 1: Tx DC Test Points

Test Point Description Value

1 PA_ON 2.86V for PA turning on, 0 V for turning off 2 PA_R1 1.97V for high gain mode,1.38V for low gain mode 3 LOCK_DET 2.95V for Lock, 0 V for unlock

4 TX_AGC

5 Tx IQ in 0.84 V With oscilloscope: 500 mV p-p 6 DAC_REF 1.56V 7 VREG_MSMP 2.96V 8 VREG_RFTX 2.64V

1.86V for 5dBm, 2.12V for 15dBm, 2.38V for 25dBm.

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Nokia Customer Care RF Description and Troubleshooting

Tx RF Test Points

4

2

3

1

5

Figure 6: Tx RF Test Points

Table 2 shows the test points shown in Figure 6.

Test Point Description Value

1 RFT6122 output 3dBm 2 PA input 1dBm 3 PA output 27dBm 4 RF connector 24.5dBm 5 UHF LO 0dBm at 1763.04MHz

Table 2: Tx RF Test Points

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Nokia Customer Care RF Description and Troubleshooting

Tx DC Test Points

7

8

5

6

4

Figure 7: Bottom side Tx DC test points

Table 3 shows the Tx DC test points shown in Figure 7.

1

3

2

Test Point

1 VREG_MSMP,C861 2.96V >11kΩ to ground U632,U631,U629,U1 2 VPH_PWR,C854 3 VREG_MSMC,C860

4 VREG_MSMA,C858 5 VEXT_DC,R840 6 VREG_TCXO,C857 7 VREG_RFRX,R855 8 VREG_RFTX,C856

Description Value RF Supply Lines Resistance to Ground

3.2~4.2V >550kΩ to ground U632,U7

1.91V >45kΩ to ground U632,U625

2.62V >120kΩ to ground U632,U625

3.2~5.7V ~9.3kΩ to ground Q400

2.82V >450kΩ to ground U632

2.66V >350kΩ to ground U632,U631,U629

2.64V >450kΩ to ground U632,U631,U629

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

*Note: Always measure resistance with the phone powered off

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Nokia Customer Care RF Description and Troubleshooting

Tx path troubleshooting

Tx path

Faults

Measure DC test

points at Table 1. Is

it OK?

NO

Check PM6610, MSM6025 Reheat solder joints of PM6610

YES

Measure Tx RF test

points 5

at Table 2. Is it OK

YES

NO

Rehear solder

oints of C836

Measure Tx RF test

NO

points 1

Change RFT6122

at Table 2. Is it OK

ES

Measure Tx RF test

NO

points 2

Reheat solder joints of C837, FL600, C619, U7

at Table 2. Is it OK

ES

Measure Tx RF test

points 3

Reheat solde

NO

oints of U7

at Table 2. Is it OK

ES

Measure Tx RF test

points 4

at Table 2. Is it OK

ES

If RF Antenna feed point pad

obstructed, clean the pad. Connect

System Simulator to MS antenna. Is it

OK

Reheat solder joints of F601, S601

NO

Note:

• MSM6025 is underfilled and cannot be replaced.

• Memory IC is underfilled and cannot be replaced.

• The shield case can not be reused after removal.

• After using the heatgun, replace the domesheet.

NO

Change U7

Check Antenna Module

NO

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Nokia Customer Care RF Description and Troubleshooting

Rx Troubleshooting

Rx system block diagram

Figure 8: Rx DC troubleshooting test points

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Nokia Customer Care RF Description and Troubleshooting

Rx introduction

The RFR6122 IC (Figure 8) provides the Zero-IF receiver signal path for Cellular-CDMA reception. For this chipset, Cellular-CDMA refers to band classes 0 and 3 as defined by the cdma2000 standard, with mobile station receivers operating between 832 and 894 MHz. The Rx signal path includes the LNA, quadrature downconversion, and baseband functions. The Cellular-CDMA received signal is routed from the antenna to the RFR6122 IC via the duplexer. The analog baseband outputs interface with one of Qualcomm’s Mobile Station MSM6025 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.

Main RX component

RX Saw filte

RX IC

6088 (RM-218)

Nokia Customer Care RF Description and Troubleshooting

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 9: FTM dialog box

6088 (RM-218)

Nokia Customer Care RF Description and Troubleshooting

Cell Receiver Check from RF to IQ

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

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

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

3. Measure a 300 kHz tuning on the analyzer. You should see a typical -48 dBm IQ

tuning for CDMA Cell.

Figure 10: Receiver IQ level on CDMA Cell band

6088 (RM-218)

Nokia Customer Care RF Description and Troubleshooting

Figure 11 shows the Cell spectrum with an inject tone at -75 dBm, as well as the IQ output test points. Note that DC is present on the IQ output test points. All test points should be approximately equal.

RX _QP RX _QN RX _ IN RX _ IP

Figure 11: Cell spectrum (left) and IQ output test points (right)

6088 (RM-218)

Nokia Customer Care RF Description and Troubleshooting

Receiver DC Test Points

1

3

2

Figure 12: Rx DC troubleshooting test points

Table 4 includes the descriptions and values for Rx DC troubleshooting test points shown in Figure 12.

Test Point Description Value

1 VREG_MSMP ,R800 2.96V 2 VREG_RFRX,R7563 2.58V 3 LNA BIAS,L800 2.58V

Table 4: Rx DC Test Points

6088 (RM-218)

Nokia Customer Care RF Description and Troubleshooting

Receiver RF Test Points

For the test points in Figure 13, an external signal source of –25 dBm was injected to the RF input. Set LNA GAIN STATE = 3 .The signal was then traced throughout the

receiver chains. An CMU200 call box is recommended. (Open non-signaling mode, 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 were taken with the RF Probe. Signal levels are approximate, and the accuracy may be +/- 2 dB or more depending on the probe position and grounding.

2

3

Figure 13: Receiver RF troubleshooting test points

Table 5 includes the descriptions and values for Rx RF troubleshooting test points shown in Figure 13.

1

Test Point Description Value

1 LNA IN -27dBm 2 RX SAW INPUT -47dBm 3 RX SAW OUTPUT -50dBm

Table 5: Rx RF Test Points

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Nokia Customer Care RF Description and Troubleshooting

Rx path troubleshooting

Rx path

Faults

Measure DC test

points at Table 4. Is

it OK?

YES

NO

Check PM6610

NO

Reheat solder joints

of PM6610

Measure Rx RF test

points 1

at Table 5. Is it OK

Reheat solder joints

NO

of C820, L802

YES

Measure Rx RF test

points 2

at Table 5. Is it OK

ES

Measure Rx RF test

points 3

NO

Reheat solder joints

of L801, C823 and

RFR6122

Reheat solder joints

of U630

NO

Change RFR6122

at Table 5. Is it OK

ES

Connect System Simulator to

Check Antenna Module

NO

MS antenna.

Note:

• MSM6025 is underfilled and cannot be replaced.

• Memory IC is underfilled and cannot be replaced.

• The Shielding Case Assy cannot be reused after removal.

• After using the heatgun, the domesheet needs to be replaced.