Nokia 6255 Service Manual 10rm19rf

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Nokia Customer Care

6255/6255i/6256/6256i (RM-19)

Mobile Terminal

RF Description and

Troubleshooting

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6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care

Contents Page

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

Mobile Terminal Components ..................................................................................................................... 6

Main PWB ......................................................................................................................................................6

UI (Secondary) PWB ....................................................................................................................................8

Preliminary RF Troubleshooting............................................................................................................... 10

Mobile Terminal Cannot Make a Call ..................................................................................................10

Tx Power Low ..............................................................................................................................................10

Transmitter RF Troubleshooting .............................................................................................................. 11

Transmitter Block Diagram .....................................................................................................................12

Transmitter Schematics ...........................................................................................................................13

Transmitter Troubleshooting Setup ......................................................................................................15

AMPS Tx Setup ....................................................................................................................................... 15

Cell Tx Setup ........................................................................................................................................... 18

PCS Setup................................................................................................................................................. 20

Transmitter RF Troubleshooting Procedures ......................................................................................22

Failed Test: Tx PA Detector ................................................................................................................. 23

Tx Output Spectrum.............................................................................................................................. 24

Tx DC Test Points - Bottom Side ....................................................................................................... 25

Tx DC and RF Test Points - Top Side................................................................................................. 26

Tx RF Test Points - Bottom Side........................................................................................................ 28

RF Power Supply DC Test Points - Bottom Side............................................................................ 29

Receiver RF Troubleshooting .................................................................................................................... 31

Receiver Block Diagram ...........................................................................................................................32

Receiver Schematics .................................................................................................................................33

RF AGC Status ............................................................................................................................................35

Turning on the Rx Path ............................................................................................................................36

Switching the Rx Gain States ................................................................................................................38

Checking AMPS from RF to IQ ........................................................................................................... 38

Checking Cell Receiver from RF to IQ.............................................................................................. 39

Checking PCS Receiver from RF to IQ.............................................................................................. 41

Receiver Diagnostic Signal Tracing ......................................................................................................42

Receiver DC Test Points........................................................................................................................ 43

Receiver RF Test Points ........................................................................................................................ 44

Receiver IF Test Points.......................................................................................................................... 45

Receiver Logic Input Voltages ................................................................................................................46

N7160 Receiver Overview .......................................................................................................................47

Synthesizer Troubleshooting .................................................................................................................... 49

Synthesizer Block Diagram .....................................................................................................................50

Synthesizer Schematics ...........................................................................................................................51

Synthesizer Troubleshooting Setup ......................................................................................................52

Incorrect PLL Frequencies.................................................................................................................... 52

VCTCXO Troubleshooting .........................................................................................................................53

VCTCXO Manual Tuning....................................................................................................................... 54

AFC Voltage Troubleshooting .................................................................................................................55

UHF Synthesizer .........................................................................................................................................56

UHF Synthesizer Test Points ............................................................................................................... 57

Rx VHF LO (N7100) Schematic ..............................................................................................................58

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Rx VHF LO Troubleshooting ....................................................................................................................59

Tx UHF LO (N7000) Schematic ..............................................................................................................60

Tx UHF LO (N7000) Troubleshooting ....................................................................................................61

GPS Troubleshooting................................................................................................................................... 62

GPS RF Block Diagram .............................................................................................................................62

GPS RF Schematic .....................................................................................................................................63

GPS Troubleshooting Setup ....................................................................................................................64

Self Test Failure...................................................................................................................................... 65

Oscillator Failure.................................................................................................................................... 65

CW Test Failure....................................................................................................................................... 65

GPS RF Troubleshooting....................................................................................................................... 65

GPS DC Test Points................................................................................................................................ 66

GPS RF Test Points................................................................................................................................. 69

FM Radio Troubleshooting ........................................................................................................................ 71

FM Radio Schematic .................................................................................................................................71

FM Radio Troubleshooting Setup ..........................................................................................................72

FM Radio Part Layouts and Probe Points........................................................................................ 72

Bluetooth Troubleshooting ....................................................................................................................... 75

Bluetooth Schematic ................................................................................................................................75

Bluetooth Troubleshooting Setup .........................................................................................................76

Bluetooth Troubleshooting Flowchart ............................................................................................. 77

Bluetooth DC and RF Test Points ...................................................................................................... 78

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Introduction

When troubleshooting the receiver, first check the RX_AGC PDM value. The AGC value should be close to the typical values in the tables. The RX AGC tries to keep a constant amplitude at the output of the receiver chain; if the AGC value indicates an AGC gain that is substantially higher than normal, the AGC is compensating for extra loss in another component. If the AGC PDM values are normal and there is still a problem, check the actual AGC voltages. RF probing at specific locations in the chain can then help to pinpoint the source of the problem.

Likewise, when troubleshooting the transmitter, first check the measured output power and AGC values, which give an indication of where to start probing.

Although probing points and signal-level information are given for each point in the receiver and transmitter chains, the troubleshooter is not expected to probe each point on every mobile terminal — only the suspected trouble spots.

Absolute power measurements were made with an Agilent (HP) 85024A active highimpedance probe. Other probes can be used (but should be high-impedance so that the measurement does not load the circuit) but may very well have a different gain; therefore, adjust the absolute measurements accordingly. Also, adjust if using a probe attenuator.

Where a range is given for loss, typically the higher loss occurs at the band edges. Probing is not a very accurate method to measure absolute power; therefore, you cannot expect measured results to exactly match the numbers listed.

Power depends on the impedance of the circuit. For example, if a filter has a nominal loss of 5dB, then straightforward probing on the input and output, then subtracting, might not result in 5dB because the input impedance might be different from the output impedance. Most components in the RF section have the same input and output impedance (50ohms), but where this is not the case absolute power is noted in dBm, rather than loss or gain in dB.

When testing the CDMA receiver, it is easier to inject a CW tone into the receiver. The gains and losses are the same for a CW signal as for CDMA.

Note: After opening the shield lids, always replace them with new lids.

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Mobile Terminal Components

The mobile terminal includes two PWB boards, the main PWB and the UI PWB.

Main PWB

Following are the components of the main PWB.

Tx I/Q signal test points

Tx power detector

Rx I/Q signal test points

Figure 1: Main PWB component layout - top

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Cell coupler

Diplexer

Antenna connector

VCO

PCS PA

Cell PA

Cell Tx filter

PCS Tx filter

N7000: Tx Upconverter

PCS coupler

Cell duplexer

PCS duplexer

Synthesizer IC

Headset jack

Rx RF Cell filter

N7160: Rx front-end

Rx RF PCS filter

Rx IF AMPS filter

VCTCXO

Rx IF CDMA filter

N7100: Rx downconverter

FM radio IC

D2800 processor

Flash

Tomahawk connector

UEM

Bluetooth IC

Figure 2: Main PWB component layout - bottom

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UI (Secondary) PWB

Following are the components of the UI PWB.

GPS ceramic filter

GPS LNA

GPS SAW filter

Figure 3: UI PWB component layout - top

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GPS antenna connector

GPS RF IC

GPS BB IC

GPS ceramic antenna

GPS antenna matching circuitry

GPS 16.368 MHz TCXO

Figure 4: UI PWB component layout - bottom

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Preliminary RF Troubleshooting

The following sections identify steps to troubleshoot some common RF issues.

Mobile Terminal Cannot Make a Call

Verify the following if the mobile terminal cannot make a call:

1. The mobile terminal is in Normal Mode (i.e., the mobile terminal is searching for a signal, net server is on).

2. The Preferred Roaming List (PRL) is loaded into the mobile terminal.

3. The mobile terminal is tuned and has passed tuning. Read the tuning parameters using the Read Parameters component in Phoenix. An untuned mobile terminal has all zeros in the tuning file.

4. The call box channel is set for a channel in PRL.

5. The SID is correct and entered into the mobile terminal.

6. The VCTCXO is centered as described in the "VCTCXO Manual Tuning" section on

7. The transmitter and receiver are working properly in Local Mode. See

Tx Power Low

Complete the following steps if Tx power is low:

1. Use Phoenix to turn on the transmitter in Local Mode.

2. Perform a visual inspection of the PWB under a microscope to check for the

3. Look for the presence of a Tx signal on a spectrum analyzer at the correct

page 54.

"Transmitter RF Troubleshooting" on page 11 and "Receiver RF Troubleshooting" on page 31 for detailed information.

proper placement, rotation, and soldering of components.

frequency.

• If a signal is present but off-frequency, check the synthesizers for proper

frequency and amplitude. One of the synthesizers may be unlocked or the VCO has no output signal.

• If a signal is not present or is present but is low in amplitude, check the

probing diagrams to determine where in the chain the fault occurs. (See "Tx RF Test Points - Bottom Side" on page 28.)

4. Ensure that the power supplies to the Tx have the correct voltage. (See "Tx DC Test Points - Bottom Side" on page 25)

5. Ensure that the AGC PDMs are set for the desired Tx power and that the AGC voltages are correct. (See "AMPS Tx Setup" on page 15, "Cell Tx Setup" on page 18, or "PCS Setup" on page 20.)

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Transmitter RF Troubleshooting

Following are the main Tx RF components.

Antenna connector

Diplexer

Cell coupler

PCS coupler

TOP SIDE

PCS Tx SAW filter

Cell PACell Tx SAW filter

PCS PA

BOTTOM SIDE

Power detector

Power switch

PCS duplexer

Cell duplexer

Figure 5: Main transmitter RF components

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Transmitter Block Diagram

Following is the block diagram for the Tx RF system.

N7000 Tx IC

Figure 6: Tx system block diagram

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Transmitter Schematics

The following schematics are for general reference only. See the Schematics chapter for detailed versions.

Cell Tx filter

N7000 Tx IC

PCS Tx filter

Tx LO lock voltage

Loop filter

Figure 7: Transmitter schematic 1

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PCS PA

Component changes based on PA manufacturer

Cell PA

PCS duplexer

Diplexer

Couplers

Power detector

Cell duplexer

Figure 8: Transmitter schematic 2

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Transmitter Troubleshooting Setup

Use the following sets of procedures to troubleshoot the transmitter using Phoenix. Due to the compact layout of the mobile terminal, some of the major test points are not accessible without destroying the shield frames and the EL lamp. For example, duplexers/ diplexer/couplers test points are blocked by the test jig, the PA test points are underneath the shield frame, and the BBIQ points are underneath the EL lamp.

To minimize effort, check the following in order:

1. Tx power at the RF connector.

2. All Tx DC points.

3. All soldering jig points for the whole Tx chain.

4. UHF LO presence:

• If the UHF LO is present, check the N7000 output.

• If the UHF LO is not present, it is a synthesizer problem.

5. If there is no N7000 output:

6. If there are several failed mobile terminals with the same symptoms, it may be

Use the following sections to set up troubleshooting in Phoenix according to the band you are using:

• "AMPS Tx Setup" on page 15

• "Cell Tx Setup" on page 18

• "PCS Setup" on page 20

AMPS Tx Setup

Use the following procedures to prepare for AMPS Tx troubleshooting using Phoenix.

1. Connect the RF test connector to a spectrum analyzer.

2. Connect the mobile terminal to the PC via a test jig. (The bottom connector is a

a. Change the N7000.

b. If the problem persists, reflow the duplexers, diplexer, and couplers.

c. If the problem persists, change the PA.

necessary to break one to determine the cause.

USB port.)

3. Connect a power supply to the mobile terminal.

4. Open the Troubleshooting menu, and click Phone Control.

The Phone Control dialog box appears.

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5. Click the LOCAL button in the Phone State area to put the mobile terminal into Local Mode.

Figure 9: Phone Control dialog box

6. Open the Troubleshooting menu, point to AMPS, and click AMPS Control.

The AMPS Control dialog box appears.

Figure 10: AMPS Control dialog box

7. Click the Tx Control tab.

8. In the Set Channel field, type 384.

9. In the Power Level field, type 5.

10. Select the Transmitter ON option, and click Execute.

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11. Configure the spectrum analyzer using the following values:

• Center Frequency = 836.52 MHz

• Span = 100 MHz

• Amplitude = 20 dBm

• Attenuation = Auto

• BW = Auto

Table 1: RF PDM Values at Power Level 5

Description/Field Reference Value

AGC1 -512

AGC2 -31

AGC3 -400

Rx IF AGC -234

AFC +176

Pout at RF connector +14dBm

Current 400-500mA

Figure 11: RF PDM dialog box for AMPS

12. Click Read Phone to update the values.

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Cell Tx Setup

Use the following procedures to prepare for Cell Tx troubleshooting using Phoenix.

1. Connect an RF test connector to a call box.

2. Connect the mobile terminal to the PC via a test jig. (The bottom connector is a USB port.)

3. Connect a power supply to the mobile terminal.

4. On the Phone Control dialog box, click the LOCAL button in the Phone State area to put the mobile terminal into Local Mode. (See Figure 9 on page 16.)

5. Open the Troubleshooting menu, point to RF, and click RF Main Mode.

The RF Main Mode dialog box appears.

Figure 12: RF Main Mode dialog box for Cell Mode

6. Select the following values on the RF Main Mode dialog box:

• Band = Cell (CDMA)

• Channel = 384

• Mode = Rx/Tx

7. Click Set.

Note: Be sure that the “RF Main Mode set successfully” message appears in the status bar.

8. Open the Troubleshooting menu, point to RF, and click CDMA Control.

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The CDMA Control dialog box appears.

Do NOT select this option

Figure 13: CDMA Control dialog box for Cell Tx troubleshooting

9. Select the following values:

• State = Rho ON

• Band = Cell

• Radio Configuration = Mode 1: IS-95 Voice

Note: Do NOT select the Set default PDM values option

10. Click Execute.

11. Configure the spectrum analyzer using the following values:

• Center Frequency = 836.52 MHz

• Span = 100 MHz

• Amplitude = 20 dBm

• Attenuation = Auto

• BW = Auto

Table 2: RF PDM Values

Description/Field Reference Value

AGC2 -250

AGC3 -387

Pout at RF connector +20dBm

Current 500-600mA

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PCS Setup

Use the following procedures to prepare for PCS Tx troubleshooting using Phoenix.

Figure 14: RF PDM Control dialog box for Cell band

12. Click Read Phone to update the values.

1. Connect an RF test connector to a call box.

2. Connect the mobile terminal to the PC via a test jig. (The bottom connector is a USB port.)

3. Connect a power supply to the mobile terminal.

4. Open the Troubleshooting menu, and point to Phone Control.

The Phone Control dialog box appears. (See Figure 9 on page 16.)

5. Click the LOCAL button in the Phone State area to put the mobile terminal into Local Mode.

6. Open the Troubleshooting menu, point to RF, and click RF Main Mode.

The RF Main Mode dialog box appears. (See Figure 12 on page 18.)

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7. Select the following values on the RF Main Mode dialog box:

• Band = PCS (CDMA)

• Channel = 600

• Mode = Rx/Tx

8. Click Set.

Note: Be sure that the “RF Main Mode set successfully” message appears in the status bar.

9. Open the Troubleshooting menu, point to RF, and click CDMA Control.

The CDMA Control dialog box appears. (See Figure 13 on page 19.)

10. Select the following values on the CDMA Control dialog box.

• State = Rho ON

• Band = PCS

• Radio Configuration = Mode 1: IS-95 Voice

Note: Do NOT select the Set default PDM values option.

11. Click Execute.

12. Open the Troubleshooting menu, point to RF, and click PDM Control.

13. Configure the spectrum analyzer using the following values:

• Center Frequency = 1880 MHz

• Span = 100 MHz

• Amplitude = 20 dBm

• Attenuation = Auto

• BW = Auto

Table 3: RF PDM Values

Description/Field Reference Value

AGC2 -511

AGC3 -83

Pout at RF connector +23dBm

Current 700-800mA

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Figure 15: RF PDM Control dialog box for PCS band

14. Click Read Phone to update the values.

Transmitter RF Troubleshooting Procedures

After Phoenix is set up using either the AMPS, Cell, or PCS setup procedures, use the following steps to troubleshoot the transmitter.

1. Using a voltmeter, check to see that all VR2, VR6, and VR1B are on the transmit system. (See "Tx DC Test Points - Bottom Side" on page 25.)

• If any are missing, look for SMD problems around the N7000 and the UEME.

• If SMD is good, replace the UEME.

2. Once all DC voltages are present, check the AGC control voltages. (See "AMPS Tx Setup" on page 15, "Cell Tx Setup" on page 18, or "PCS Setup" on page 20.)

• If the voltages are incorrect, check the SMD around TX_AGC1 and TX_AGC2.

• If the SMDs are correct, replace the D2800.

3. Using an oscilloscope, check the input modulation BBIQ wave forms at R7021, R7022, R7023, and R7024. They should all be present with an AC swing of about 500mVpp, with an offset of +1.2V.

• If one or more waveforms are missing, look for SMD problems around these

resistors.

• If the SMD is good, replace the UEM.

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4. Use an AAS-10 RF probe to probe the Cell Tx output of the N7000.

• If there is no RF or low RF, look for SMD everywhere around the N7000.

• If the SMD is okay, replace the N7000.

5. Probe the PA input.

• If the level is low, look for an SMD issue on the Tx filter or matching

transformer (T7001 or T7002).

• Reflow or replace the filter as necessary.

6. Probe the PA output.

• If the RF is missing or low, look for Vbatt voltages and SMD issues on and

around the PA.

• If these are okay, replace the PA.

7. Probe the duplexer output.

• If the RF is missing or low, reflow or replace the duplexer.

8. Probe the coupler output.

• If the RF is missing or low, reflow or replace the coupler.

9. Probe the diplexer output.

• If the RF is missing or low, reflow or replace the diplexer.

Failed Test: Tx PA Detector

Use the following steps if you encounter a failed test for the Tx PA detector:

1. Use Phoenix to set the mobile terminal into Local Mode and activate the Tx with default output power.

2. The output power at the RF test connector should be 15dBm +/- 4dB. If not, follow the procedures in the "Transmitter RF Troubleshooting Procedures" section on page 22.

3. Using a voltmeter on DC, probe the detector output at C7313. The voltmeter should read approximately 1.4V. If not, replace N7300. (See page 26 for test point locations and common power and voltage variations.)

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Tx Output Spectrum

Following is the correct output of the mobile terminal on a spectrum analyzer with 100MHz span. Note that if you are using the AAS-10 probe with the mobile terminal connected to the call box, the amplitude should be approximately -7dBm at the antenna test point on the top of the PWB.

Figure 16: Correct output spectrum

Following is an example of incorrect output.

Figure 17: Incorrect output spectrum

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Tx DC Test Points - Bottom Side

Following are the Tx DC test points located on the bottom side of the main PWB.

2 3

Figure 18: Tx DC test points on the bottom side of the main PWB

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Table 4 shows the values for the test points in Figure 18.

Table 4: Tx DC Test Point Description and Values - Main PWB - Bottom Side

Test Point

1 Tx UHF LO Lock voltage: ~1.2V

2VR6 2.8V

3 Vbatt Cell*

4 Vbatt PCS*

5VR1B 4.8V

6AGC1 0.1V to 1.8V

7AGC2 0.1V to 1.8V

8VR6 2.8V

9VR2 2.8V

10 VR1B 4.8V

Description Values

*Vbatt also appears at the outputs of the PAs.

Tx DC and RF Test Points - Top Side

Following are the Tx DC and RF test points located on the top side of the main PWB.

Figure 19: Tx DC and RF test points on the top side of the main PWB

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Table 5 shows the values for the test points in Figure 19.

Table 5: Tx DC Test Point Description and Values - Main PWB - Top Side

Test Point

1 Power detector input AMPS: -5dBm at 836.25MHz

2 Power detector output AMPS/Cell:

3 Power detector VR2 2.8V

4AGC2 0.1V to 1.8V

5AGC1 0.1V to 1.8V

6 Tx IQ in ~1.2V

Description Values

Cell: -3dBm at 836.25MHz PCS: -6dBm at 1880MHz

1.9V at <5dBm

1.8V at 15dBm

1.2V at 25dBm

PCS:

1.9V at <5dBm

1.8V at 15dBm

1.3V at 25dBm

With oscilloscope: Approximately 500 mV p-p with +1.2V offset

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Tx RF Test Points - Bottom Side

Figure 20 shows the Tx RF test points located on the bottom side of the main PWB.

Figure 20: Tx DC and RF test points on the bottom side of the main PWB

Table 6 shows the values for the test points in Figure 20. These values are based on a PCS frequency of 1880MHz and an AMPS/Cell frequency of 836.25MHz.

Table 6: Tx RF Test Point Descriptions and Values - Main PWB - Bottom Side

Test Point

1 Tx UHF LO Cell: 3346.08MHz -57dBm

2 PCS N7000 out -15dBm

3 Cell N7000 out Cell: -8dBm

Description Values

PCS: 3760MHz -54dBm

AMPS: -15dBm

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Table 6: Tx RF Test Point Descriptions and Values - Main PWB - Bottom Side (Continued)

Test Point

4 PCS PA out 11dBm

5 RF out AMPS: +14dBm

Description Values

RF Power Supply DC Test Points - Bottom Side

Following are the RF power supply DC test points located on the bottom side of the main PWB.

Cell: +20dBm PCS: +20dBm

2 3

Figure 21: RF power supply DC test points on the bottom side of the main PWB

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Table 7 shows the values for the test points in Figure 21.

Table 7: RF Power Supply DC Test Points (Main PWB - Bottom Side)

Probe Point

1 VIO 1.8V

2 VrefRF1 1.4V (Tx)

3 VR7 2.8V (Rx)

4 VR6 2.8V (Tx)

5 VR2 2.8V (Tx)

6 VR3 2.8V (Synthesizer)

7 VR5 2.8V (Rx)

8 VR4 2.8V (Rx)

9 VR1A 4.7V (Synthesizer)

10 VR1B 4.7V (Tx)

Description Value

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Receiver RF Troubleshooting

The heart of the receiver is the N7160 Rx IC, which contains two LNAs and mixers. The other components are passive. There are two RF SAW filters for the Cell and PCS bands. In addition, there are two additional IF filters, an IF SAW for CDMA and an IF Crystal for AMPS. The back-end of the receiver consists of the N7100 IC, which handles the VGA and IQ demodulator functions.

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Receiver Block Diagram

Following is the Rx system block diagram.

Figure 22: Receiver system block diagram

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Receiver Schematics

The following schematics are for general reference only. See the Schematics chapter for detailed versions.

Cell RF SAW filter

N7160 Rx front-end IC

PCS RF SAW filter

AMPS IF crystal filter

CDMA IF SAW filter

Figure 23: Receiver schematics - 1

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Loop filter

Rx LO lock voltage

1.2 to 1.7 Vdc

N7100 Rx downconverter

Figure 24: Receiver schematic - 2

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RF AGC Status

When configuring the values on the RF AGC Status dialog box, note the following:

• The RF AGC status functionality only works in Call Mode.

•In the PLL Lock Status area, bright green indicates a locked PLL and dark green indicates an unlocked PLL.

•In the Baseband Type field, ensure that the correct baseband is selected (Tiku BB 4.5).

• Clicking the Stop Updating button allows you to toggle between the Update Every 2 Seconds and Stop Updating functions.

AFC PDM settings

LNA Gain (High[Boost for PCS]/Low)

Rx IF AGC PDM settings

BBAMP Gain Settings

PA AGC PDM settings

Figure 25: RF AGC Status dialog box

Tx AGC 2 PDM settings

Tx AGC 1 PDM settings

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Turning on the Rx Path

Use the following steps to turn on the Rx path using Phoenix.

1. On the Phone Control dialog box, click the LOCAL button in the Phone State area to put the mobile terminal into Local Mode.

Figure 26: Phone Control dialog box

2. Click the Execute button.

3. Depending on the band, use the applicable settings from the table below on the

RF Main Mode dialog box.

Table 8: RF Main Mode Dialog Box Settings

Band Mode Channel

AMPS Rx = 881.52 MHz 384

Cell Rx = 881.52 MHz 384

PCS Rx = 1960 MHz 600

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Figure 27: RF Main Mode dialog box for AMPS (top), Cell (middle), and PCS (bottom)

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Switching the Rx Gain States

Use the RF Gen I/O dialog box to switch the gain state (Hi and Lo) for CDMA and AMPS modes.

High Gain State (default)

Cell

AMPS

Low Gain State

PCS

Checking AMPS from RF to IQ

Use the following steps to check the AMPS receiver functionality from RF to IQ output.

1. Start Phoenix in Local Mode with only the Rx path turned on.

2. Inject a –75dBm CW signal of 881.53MHz (i.e. 10kHz offset from 881.52MHz) into the RF.

3. Measure a 10kHz tone on the analyzer. You should see a typical -20Bm IQ tone for AMPS.

CDMA

Figure 28: RF Gen I/O dialog box

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Figure 29: Receiver IQ Level on AMPS band

Figure 30 shows the AMPS spectrum and the test points located on the top side of the main PWB. All four test points should be approximately equal. WARNING: Direct current is present on these test points.

Figure 30: AMPS spectrum and the test points on the top side of the main PWB

Checking Cell Receiver from RF to IQ

Use the following values to check the Cell receiver functionality RF to IQ output.

Rx_IP

Rx_IN

Rx_QP Rx_QN

1. Start Phoenix in Local Mode with only the Rx path turned on.

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

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3. Measure a 300kHz tone on the analyzer. You should see a typical -21dBm IQ tone for CDMA Cell.

Cell I Q Output

dBm 0

-10

-20

-30

-40

-50

-60

-70

Trace A

Trace A 302 kHz

-21.2500 dB

-80

-90

-100 Centre: 300 kHz Span: 200 kHzAtten: 10 dB

Res BW: 3 kHz Vid BW: 3 kHz Sweep: 100 ms 5/5/2004 3:29:30 PM HP8595ECellIQ.spt

Figure 31: Receiver IQ level on Cell band

Figure 32 shows the Cell spectrum and the test points located on the top side of the main PWB. All four test points should be approximately equal. WARNING: Direct current

is present on these test points.

Rx_IP

Rx_IN

Rx_QP Rx_QN

Figure 32: Cell spectrum and test points on the top side of the main PWB

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Checking PCS Receiver from RF to IQ

Use the following values to check the PCS receiver functionality from RF to IQ output.

1. Start Phoenix in Local Mode with only the Rx path turned on.

2. Inject a –75dBm CW signal of 1960.5MHz (i.e. 500kHz offset from 1960MHz or 10 channels away).

3. Measure a 500kHz tone on the analyzer. (If a 300kHz tone works but a 500kHz tone does not, the problem is in the BB filter, possibly not set by Phoenix.) You should see a typical -22dBm IQ tone for CDMA PCS.

Figure 33: Receiver IQ Level on PCS Band

Figure 33 shows the PCS spectrum and the test points located on the top side of the main PWB. All four test points should be approximately equal. WARNING: Direct current

is present on these test points.

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Figure 34: PCS spectrum and the test points on the top side of the main PWB

Receiver Diagnostic Signal Tracing

Use the following steps to trace the receiver signal.

1. Inject an external signal source of –25dBm to the RF input. An Agilent call box 8960 is recommended.

2. Press the Call Setup button, press the Active Cell soft button, and select CW.

3. Inject a CW signal for PCS (1960MHz) or Cell/AMPS (881.52MHz) at a fixed

-25dBm power level.

Rx_IP

Rx_IN

Rx_QP Rx_QN

4. Use an AAS-10 probe to take measurements. Signal levels are approximate, and accuracy may be +/- 2dB or more depending on the position and grounding of the probe.

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Receiver DC Test Points

Figure 35: Receiver DC troubleshooting test points on the bottom side of the main PWB

Table 9 includes the descriptions and values for the Rx DC test points from Figure 35.

Table 9: Receiver DC Test Point Values

Test Point

1 Rx LO lock voltage 1.2 to 1.7 Vdc

2 LO Vdd 2.6 VDC LO Amp supply lines

3 RFA Vdd 2.8 VDC RF Amp Vdd supply

Description Value

for Cell and PCS

line for Cell band

4 C_LNA Vdd 2.8 VDC external VDd supply

line for Cell LNA

5 P_LNA Vdd 2.8 VDC external Vdd supply

line for PCS LNA

6 IFA Vdd 2.8 VDC IF Amp Vdd supply line

for CDMA and AMPS IFs

7 IFA Vdd 2.8 VDC IF Amp Vdd supply line

for CDMA and AMPS IFs

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Receiver RF Test Points

Figure 36: Rx RF test points on the bottom side of the main PWB

Table 10 includes the descriptions and values for the Rx RF test points from Figure 36.

Table 10: Receiver RF Test Point Values

Test Point

Description Value

1 PCS_CEL_LO (from VCO) Cell: 1009.62MHz at -15dBm

PCS: 2088.1MHz at -17dBm

2 Cell channel 384 (from duplexer) 881.52MHz at -33dBm

3 Cell channel 384 (to RF SAW) High gain: 881.52MHz at -21dBm

Low gain: 881.52MHz at -36dBm

4 PCS channel 600 (from duplexer) 1960MHz at -46dBm

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Table 10: Receiver RF Test Point Values (Continued)

Test Point

5 PCS channel 600 (to RF SAW) High gain: 1960MHz at -32dBm

6 IF MIX OUT (from N7160) High gain: 128.1MHz at -21dBm

7 IFA_IN (to N7160) High gain: 128.1MHz at -18dBm

Receiver IF Test Points

Description Value

Low gain: 1960MHz at -49dBm

Low gain: 128.1MHz at -34dBm

Figure 37: Receiver IF test points on the bottom side of the main PWB

Table 11 includes the descriptions and values for Rx IF test points from Figure 37.

Table 11: Receiver IF Test Point Values

Test Point

1 Rx VHF LO 256.2MHz at -70dBm

2 CDMA IF (to SAW) 128.1MHz High gain: Cell channel 384 at -9dBm

Description Value

Low gain: Cell channel 384 at -25dBm High gain: PCS channel 600 at -8dBm Low gain: PCS channel 600 at -24dBm

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Table 11: Receiver IF Test Point Values (Continued)

Test Point

3 CDMA_IF_P (to the N7100)

4 CDMA_IF_N Cell high gain: -29dBm

5 AMPS IF (to MCF) 128.1MHz High gain: Cell channel 384 at -19dBm

6 AMPS_IF_N (to the N7100)

7 AMPS_IF_P Cell high gain: -28dBm

Description Value

128.1MHz

Receiver Logic Input Voltages

Figure 38 shows the receiver logic input voltages.

Cell high gain: -29dBm Cell low gain: -45dBm PCS high gain: -29dBm PCS low gain: -45dBm

Cell low gain: -45dBm PCS high gain: -29dBm PCS low gain: -45dBm

Low gain: Cell channel 384 at -35dBm

Cell high gain: -28dBm Cell low gain: -44dBm

Cell low gain: -44dBm

Figure 38: Receiver logic input voltage test points

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Table 12 includes the measure logic levels for the N7160.

Table 12: Rx Front-end (N7160) Logic Levels

Logic Input Voltages

Mode

IF_SEL BAND GAIN_CTL

AMPS High Gain 2.8 V 0.1 V 2.8 V

AMPS Low Gain 2.8 V 0.1 V 0 V

Cell CDMA High Gain 0 V 0.1 V 2.8 V

Cell CDMA Low Gain 0 V 0.1 V 0 V

PCS CDMA High Gain 0 V 2.7 V 2.8 V

PCS CDMA Low Gain 0 V 2.7 V 0 V

If the logic levels are significantly off (+/- 0.2V), replace the N7160 and re-measure. If the voltages are still out of specifications, refer to the Baseband Troubleshooting chapter.

N7160 Receiver Overview

Keep the following points in mind regarding the N7160 receiver:

• There is a separate LNA for 800MHz (Cell and AMPS) and 1900MHz (PCS).

• There is a separate RFA (inside N7160) for 800MHz (Cell and AMPS) and 1900MHz (PCS).

• After the RFA, there is a mixer, and then the signals are separated by CDMA (Cell and PCS) and AMPS.

For example, if there is no IF frequency (128.1MHz) check both Cell and PCS. If only one has 128.1MHz at L753, ensure that IF_SEL is working. If it is, then replace the N750 due to a bad RFA.

If Cell and AMPS are working but PCS is not, look at the band select line and the PCS LNA before replacing the N7160.

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Cell LNA

PCS LNA

IFAs

LO Buffer

Cell RFA

PCS RFA

Figure 39: N7160 receiver

There are two common explanations for an N7160 failure consisting of high current in Local Mode with just the Rx turned on:

• No presence of an LO signal

• Input impedance drop is shorting out one of the DC supply pins to the chip

IMPORTANT: You must check for both conditions before replacing the chip. If you have no LO signal, refer to "UHF Synthesizer" on page 56. If you have a significant supply voltage drop on one of the supply pins, then replace the N7160.

Table 13: N7160 Conditions and Supply Currents

Condition: Local Mode, Set Rx Only in RF Main Mode

Good mobile terminal 100mA

No UHF LO signal present 254mA

Pin 13 shorted 255mA

Supply Current (From Power Supply)

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Synthesizer Troubleshooting

Faulty synthesizers can cause both Rx and Tx failures during tuning, in addition to the VCTCXO tuning. However, first check for the presence of various LO signals and their proper levels. If everything fails, it may be necessary to check the reference clock (19.2MHz) which is needed for the mobile terminal to power up. The 19.2MHz signal is also important because the D2800 processor is sensitive enough to pick up a very weak

19.2MHz clock, resulting in intermittent problems such as a constant mobile terminal reset.

Following are the synthesizers used in the mobile terminal:

• Dual-band UHF (1009.62MHz for channel 384 in Cell and AMPS bands, and

2088.1MHz for channel 600 in PCS band) with a separate LMX2310 PLL IC

• Rx VHF (256.2MHz for Cell, AMPS, and PCS) with PLL inside the N7100 IC

• Tx UHF (3296.16MHz~3395.88 for Cell and AMPS, 3700~3819.9MHz for PCS) with PLL inside the N7000 IC

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Synthesizer Block Diagram

Rx VHF LO

256.2MHz

N7100

UHF LO

1009.62MHz (Cell ch. 384)

2088.1MHz (PCS ch. 600)

D2800

N7160

N7200

Tx UHF LO

3395.88MHz

3819.90MHz

N7000

Figure 40: Synthesizer block diagram

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Synthesizer Schematics

The following schematics are for general reference only. See the Schematics chapter for detailed versions.

VCTCXO with AFC control

UHF PLL IC

19.2MHz buffer Not installed

Loop filter components

Figure 41: Synthesizer schematic

Lock voltage

Dual-band VCO

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Synthesizer Troubleshooting Setup

Use the following steps to troubleshoot the synthesizer using Phoenix:

1. On the Phone Control dialog box, click the LOCAL button in the Phone State area to put the mobile terminal into Local Mode.

2. Select the following values on the RF Main Mode dialog box:.

Synthesizer Band Mode Channel

UHF

Rx VHF (one band is enough) Rx

Tx VHF Cell Rx/Tx 384

Incorrect PLL Frequencies

Following are some possible causes for incorrect PLL frequencies:

• Power supplies to PLL portion

• Control line to VCO

• Loop filter or resonator components missing or incorrectly installed

Figure 42: Phone Control dialog box

Table 14: RF Main Mode Dialog Box Settings

Cell Rx/Tx 384

PCS Rx/Tx 600

• 19.2MHz reference clock missing or low

• Component failure (PLL IC, N7100, N7000, VCO, or VCTCXO)

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VCTCXO Troubleshooting

Without 19.2MHz, the mobile terminal does not power up. This signal goes to the N7100, N7000, D2800, and the UHF PLL. Check the test points in Figure 43 for the presence of the 19.2MHz signal.

Dual-band VCO

VCTCXO

Figure 43: VCTCXO test point output values

4 5

UHF PLL IC

Table 15 includes the descriptions and values for VCTCXO test points from Figure 43.

Table 15: VCTCXO Test Point Output Values

Test Point

1 F_REF_TX, clock reference to the N7000 ~ -9dBm

2 F_REF_RX, clock reference to the N7100 ~ -9dBm

3 CLK19M2_TIKU, clock reference to Tiku ~ -9dBm, and ~2 dB less on the other side

Description Value

of R7204 (located adjacent to the D2800)

4 CLK19M2_LPRF, clock reference to the

Bluetooth subsystem

5 CLK19M2_GPS, clock reference to the

GPS subsystem

6 OSC IN to UHF PLL

~ -9dBm

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Table 15: VCTCXO Test Point Output Values (Continued)

Test Point

7 If you do not see the VCTCXO signal at

8 AFC voltage 1 to 3 Volts (adjustable with the AFC slider

N/A If an AFC voltage is missing, check the

Description Value

test points 1-5, check the voltage at VR3

UEM.

VCTCXO Manual Tuning

The VCTCXO can be manually tuned to verify when a mobile terminal is tuned incorrectly or if mobile terminal cannot make a call. Monitor the RF signal at the mobile terminal’s output.

1. On the Phone Control dialog box, click the LOCAL button in the Phone State area to put the mobile terminal into Local Mode. (See Figure 9 on page 16 for an example of the Phone Control dialog box.)

2.8V

on the RF PDM Control in Phoenix)

1.2V for PDM 0 0V for PDM -1024

2.4V for PDM 1024

2. Click the Execute button.

3. On the AMPS Control dialog box, set the Set Channel field to 384, the Power Level field to 5, and select the Transmitter ON check box. (See Figure 10 on page 16 for an example of the AMPS Control dialog box.)

4. Click the Rx RFI tab, make sure the AFC Control check box is cleared, and click Execute.

5. The frequency accuracy of the VCTCXO can be measured using an HP8960 callbox in AMPS mode or a spectrum analyzer at the output of the transmit chain.

• If using a spectrum analyzer, set the center frequency to 836.52MHz and the

span to 2MHz initially. Establish a marker at 836.52Mhz.

• If using an HP8960, set the callbox System Type to AMPS, and set the ACC

channel to 384. Use the Frequency Stability measurement to center the VCTCXO (minimum Frequency Error).

6. Use the RF PDM component to adjust the AFC to center the VCTCXO. The tuning range is approximately +/-10kHz.

7. Adjust the AFC so that the output signal is within +/-150MHz. If using a spectrum analyzer, narrow the span to 1kHz or less.

8. Replace the UEM if the VCTCXO does not tune correctly.

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AFC Voltage Troubleshooting

Use the following steps to monitor the AFC voltage.

1. In Phoenix, open the RF PDM dialog box.

Figure 44: RF PDM dialog box for AFC troubleshooting

Figure 45 shows a partial schematic of the R7205.

Figure 45: Partial schematic showing the R7205

2. Measure the DC voltage at R7205. The following typical voltages are shown in Figure 46.

• 1 = AFC PDM[-1024]=0V

• 2 = AFC PDM[0]=1.2V

• 3 = AFC PDM[1024]=2.4V

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UHF Synthesizer

The UHF LO frequency varies with the channel and can be calculated using the Frequency Calculator dialog box in the Phoenix RF component. Use the following steps to troubleshoot the UHF LO frequency.

1. Ensure that the LO is locked. Set a channel and check the output of the UHF LO at L7200 within a very narrow span of 100KHz. The LO must be virtually immobile.

2. Measure the nominal UHF LO signal levels (see "UHF Synthesizer Test Points" on page 57).

3. If you do not see the presence of any LOs, check the DC voltages at the following:

• R7209, VR4, supply line for VCO IC and PLL IC = 2.76VDC

4. If the frequency of the LO is not correct, check the DC voltages at the following:

• R7208, VR1A, supply line for PLL charge pump = 4.76VDC

5. Ensure that the lock voltage at C7220 is between 1V and 3V.

6. Check the RF return at R7210.

Figure 46: Tx Output for AMPS channel 384, power level 5

• TX UHF LO (Cell/AMPS) = Tx frequency x 4

• TX UHF LO (PCS) = Tx frequency x 2

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UHF Synthesizer Test Points

N7100

Figure 47: UHF synthesizer layout

Table 16 shows the description for each component in Figure 47.

Table 16: UHF Synthesizer Layout Components

Test Point

1 BAND_SEL_VCO Cell = 0Vdc

2 PCS_CEL-LO return to UHF PLL Cell: -11dBm

3 PCS_CEL_LO input to the N7160 Cell channel 384: 1009.62MHz > -15dBm

4 Lock voltage DC between 0.8 and 3.4V, S/B 1.2V at the

5 VR4 2.8V

6VR1A 4.8V

7VPLL 2.8V

Description Value

PCS = 2.8Vdc

PCS: -18dBm

PCS channel 600: 2088.1MHz > -17dBm

center frequency

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Rx VHF LO (N7100) Schematic

Following are the main layout components on a partial view of the Rx VHF schematic. See the Schematics chapter for detailed versions.

Loop filter

Lock voltage

components

PLL

Resonator

Figure 48: Rx VHF schematic, partial view

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Rx VHF LO Troubleshooting

The VHF LO operates at a fixed frequency of 256.2MHz. It is the second LO for downconversion to I and Q for baseband processing. Use the following steps to troubleshoot the VHF LO.

1. Monitor the test point at C710. Ensure that a locked and stable 256.2MHz with amplitude ~ –60dBm is present on the spectrum analyzer (or, with a high impedance probe, ~ -2dBm at C7104).

2. Monitor the control voltage at C7100. The control voltage at a locked state must be between 1.2 and 1.7 Vdc for the proper operation of the VHF LO.

RF Rx ASIC

AMPS IF XTAL filter

CDMA IF SAW filter

Figure 49: Rx VHF LO test points

Table 17 shows the description for each component in Figure 49.

Table 17: Rx VHF Layout Components

Test Point

Description Value

LNA/Mixer/ Downconverter

1 VIO 1.8V

2 Rx LO 256.2MHz -60 to -65dBm

3 Rx LO lock voltage 1.2 to 1.7Vdc

4 VR7 2.8V

5 VR5 2.8V

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Tx UHF LO (N7000) Schematic

The following partial schematic is for general reference only. See the Schematics chapter for complete detailed versions.

Loop filter

Lock voltage

Figure 50: Tx UHF LO (N7000) schematic

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Tx UHF LO (N7000) Troubleshooting

There are two fixed LOs, 3296.16~3395.88MHz for cell band and 3700~3819.90MHz for PCS band. This is the only LO for up-conversion. Be sure to monitor the control voltage at R7001. When the N7000 LO is locked, this control voltage should be between 1.2 and

1.8Vdc.

1 3

Figure 51: Tx UHF LO layout and test points

Table 18 shows the description for each component in Figure 51.

Table 18: Tx UHF Test Point Values

Cell PA

PCS PA

Test Point

1 Lock voltage DC between 1.2 and 1.8V

2 N7000: Measure voltage by probing

3VIO 1.8V

4 Vcc_Vco 2.3V

5VR6 2.8V

Description Value

Cell channel 384: 3346.08MHz, -55 to -65dBm

the top of the chip.

PCS channel 600: 3760MHz, -54 to -65dBm

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GPS Troubleshooting

GPS RF Block Diagram

Figure 52: GPS block diagram

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GPS RF Schematic

The following schematic is for general reference only. See the Schematics chapter for a detailed version.

GPS RF chip

RF test input

RF filter 1

GPS LNA

GPS TCXO

RF filter 2

Figure 53: GPS RF schematic

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GPS Troubleshooting Setup

Use the following steps to set up GPS signal using Phoenix.

2. Click the Execute button.

3. Inject a -110dBm tone at 1575.52MHz at the GPS connector (X6250) with a signal generator or call box.

Figure 54: X6250 on the bottom side of the UI PWB

4. Open the Troubleshooting menu, and click GPS Testing.

The GPS Control dialog box appears.

Figure 55: GPS Control dialog box

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5. In the Test Mode field, ensure that Galvanic is selected.

6. Click Execute.

Self Test Failure

If the test fails, repeat steps 1—6. If the test fails again, continue with the following selftest failure troubleshooting:

1. Verify the DC voltages at VRF_GPS and VIO_GPS. ("GPS DC Test Points" on page 66 for test point locations and values.)

2. Inspect all GPS circuit elements around the GPS BB chip (N6200).

3. If the elements pass a visual inspection, replace the N6200.

Oscillator Failure

1. Inspect all GPS circuit elements around the GPS RF chip (N6250).

2. If the elements pass a visual inspection, replace the GPS TCXO (B6250).

CW Test Failure

1. Check that the signal generator is on and sourcing a signal to the GPS RF input port (X6250).

2. Inspect all GPS RF circuit elements.

3. Probe the GPS RF test points on page 69.

4. If the elements pass a visual inspection and the RF is good, replace the GPS RF IC (N6250).

GPS RF Troubleshooting

Use the following steps to trouble shoot the GPS receiver.

1. On the GPS Control dialog box, select On.

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2. Click Execute.

Figure 56: Turning on the GPS receiver on the GPS Control dialog box

3. Inject a -50dBm tone at 1575.52MHz at the GPS connector (X6250) with a signal generator or a call box. (See Figure 54.)

GPS DC Test Points

Measure the following test points with an AAS-10B probe and spectrum analyzer set at center frequency 1575.25MHz (span = 500kHz), or with a voltmeter as required.

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BOTTOM SIDE

GPS TCXO

GPS RF connector

GPS RF IC

GPS BB IC

TOP SIDE

GPS ceramic antenna

Ceramic filter

SAW filter

Figure 57: GPS DC probe points on the bottom side (left) and top side (right) of the UI PWB

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Table 19 shows the values for the GPS DC test points in Figure 57.

Table 19: GPS DC Test Point Values

Test Point

1VIO 1.8V

2 VRF_GPS 2.8V

3 LNA base 0.8V

4LNA Vcc 1.5V

Description Value

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GPS RF Test Points

GPS RF connector

TOP SIDE

BOTTOM SIDE

GPS RF IC

GPS BB IC

GPS TCXO

GPS ceramic antenna

Ceramic filter

SAW filter

Figure 58: GPS RF probe points on the top side of the UI PWB

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Table 20 shows the values for the GPS RF test points in Figure 58. All points are

1575.52MHz, except TCXO.

Table 20: GPS RF Test Point Values

Test Point

1 GPS TCXO 16.368MHz = -19dBm

2 GPS TCXO 16.368MHz = -4dBm

3 First RF filter input -62dBm

4 First RF filter output -65Dbm

5 LNA out -48dBm

6 Second RF filter input -48dBm

Description Value

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FM Radio Troubleshooting

FM Radio Schematic

The following schematic is for general reference only. See the Schematics chapter for a detailed version.

Loop filter and VCO

FM radio IC

Audio output

FM antenna matching components

Figure 59: FM radio schematic

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FM Radio Troubleshooting Setup

Use the following steps to troubleshoot the FM radio while using a Pop-port headset.

1. Connect the Pop-port headset (HDS-3) to the Pop-port connector (bottom connector).

2. Select the Menu > Media > Radio from the mobile terminal user interface.

3. In an FM radio broadcast coverage area, set a local radio channel by scanning automatically using the Automatic tuning option. (Scanning up and down the channels by pressing the “Up” and “Down” key respectively).

4. If no channel could be found, inspect all the components in the FM radio circuitry.

• If the circuits pass a visual inspection, check the existence of the LO (by

radiative pickup) near the VCO of the FM Radio IC.

• If no LO is found, replace the FM radio IC.

5. Listen for sound out of the headset.

• If there is a signal present, continue to step 6.

• If there is no static sound present, inspect all FM Radio circuits on the PCB

and refer to the “Audio” section of the Baseband Description and Troubleshooting chapter for more information.

6. Disconnect the Pop-port headset and connect the universal headset to the UHJ (top connector).

7. With the universal headset connected, repeat steps 1—5.

• If there is a signal present, the FM Radio is working properly.

• If there is no static sound present, refer to the “Audio” section of the

Baseband Description and Troubleshooting chapter for more information.

FM Radio Part Layouts and Probe Points

Use the following values when probing the LO near the VCO of the FM radio IC (N6100). See Figure 61 for the location of the N6100.

Table 21: FM Radio Test Point Values

Description Value

LO frequency (Rx frequency + IF frequency) x 2

IF frequency 225kHz

For example, if the Rx frequency is 87.5 and the IF frequency is 225kHz, the LO equals

175.45MHz [(87.5+0.225)*2 = 175.45MHz].

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Nokia Customer Care RF Description and Troubleshooting

FM antenna matching components

Figure 60: FM radio parts on the top side of the main PWB

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6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care

FM audio coupling caps

FM radio circuitry

FM radio IC

Figure 61: FM radio parts on the bottom side of the main PWB

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Nokia Customer Care RF Description and Troubleshooting

Bluetooth Troubleshooting

Bluetooth Schematic

The following schematic is for general reference only. See the Schematics chapter for a detailed version.

Bluetooth ASIC (N6000)

Bluetooth antenna strip

SAW filter

Inverter

Supply line filtering

Voltage regulator

Figure 62: Bluetooth schematic

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Bluetooth Troubleshooting Setup

Use the following steps to troubleshoot the BC02 Bluetooth Control component in Phoenix:

1. On the Bluetooth Control dialog box, select the Tests tab.

2. In the PRBS9 list, choose TX Data 1.

3. For easy power measurement, choose “TX Simple” – 62.5kHz FM.

4. Click on “Options” button.

5. Set Internal gain = 52

6. Set Tx-Rx Frequency = 2440MHz

Table 22: Bluetooth Spectrum Analyzer Settings

Description Value

RBW 500kHz

VBW 500kHz

Center 2440MHz

Span 20MHz

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Nokia Customer Care RF Description and Troubleshooting

Bluetooth Troubleshooting Flowchart

Bluetooth

Is the VREG_IN BT

external supply

voltage 2.8V?

YES

Is the VIO bluetooth

external supply

voltage 1.8V? (Probe

at the UEM side.)

YES

Is the VDD_ANA

voltage regulator

output 1.8V?

YES

Is the XTAL_IN

450mVpp, 19MHz,

1.3Vdc?

Replace the EXT

regulator. Is it OK?

Replace the R6002.

Replace the C6002

and R6001 buffer

discretes. Is it OK?

Is it OK?

Replace the digital

inverter. Is it OK?

Replace the BT ASIC

(N6000).

YES

Are the TX_A and

TX_B power levels

each -15dBm?

YES

Is the SAW filter

output power level -

18dBm? (Probe at

the bluetooth

antenna.)

Replace the L6000,

L6001, and C6000

filter discretes. Is it

Replace the SAW

filter. Is it OK?

OK?

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6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care

Bluetooth DC and RF Test Points

Figure 63 shows the bluetooth DC and RF test points on the bottom side of the main PWB.

Digital inverter

Voltage regulator

Figure 63: Bluetooth DC and RF test points on the bottom side of the main PWB

Table 23 shows the values associated with the bluetooth test points in Figure 63.

Table 23: Bluetooth DC and RF Test Point Values

Test Point

1 XTAL_IN 19MHz, 450mVp-p/1.3V

Description Value

2 VDD_VCO 1.8V

3 VDD_ANA 1.8V

4 VREG_IN 2.8V

Nokia 6255 Service Manual 10rm19rf

Specifications and Main Features

Frequently Asked Questions

User Manual

Contents Page

Introduction

Mobile Terminal Components

Main PWB

UI (Secondary) PWB

Preliminary RF Troubleshooting

Mobile Terminal Cannot Make a Call

Tx Power Low

Transmitter RF Troubleshooting

Transmitter Block Diagram

Transmitter Schematics

Transmitter Troubleshooting Setup

AMPS Tx Setup

Cell Tx Setup

PCS Setup

Transmitter RF Troubleshooting Procedures

Failed Test: Tx PA Detector

Tx Output Spectrum

Tx DC Test Points - Bottom Side

Tx DC and RF Test Points - Top Side

Tx RF Test Points - Bottom Side

RF Power Supply DC Test Points - Bottom Side

Receiver RF Troubleshooting

Receiver Block Diagram

Receiver Schematics

RF AGC Status

Turning on the Rx Path

Switching the Rx Gain States

Checking AMPS from RF to IQ

Checking Cell Receiver from RF to IQ

Checking PCS Receiver from RF to IQ

Receiver Diagnostic Signal Tracing

Receiver DC Test Points

Receiver RF Test Points

Receiver IF Test Points

Receiver Logic Input Voltages

N7160 Receiver Overview

Synthesizer Troubleshooting

Synthesizer Block Diagram

Synthesizer Schematics

Synthesizer Troubleshooting Setup

Incorrect PLL Frequencies

VCTCXO Troubleshooting

VCTCXO Manual Tuning

AFC Voltage Troubleshooting

UHF Synthesizer

UHF Synthesizer Test Points

Rx VHF LO (N7100) Schematic

Rx VHF LO Troubleshooting

Tx UHF LO (N7000) Schematic

Tx UHF LO (N7000) Troubleshooting

GPS Troubleshooting

GPS RF Block Diagram

GPS RF Schematic

GPS Troubleshooting Setup

Self Test Failure

Oscillator Failure

CW Test Failure

GPS RF Troubleshooting

GPS DC Test Points

GPS RF Test Points

FM Radio Troubleshooting

FM Radio Schematic

FM Radio Troubleshooting Setup

FM Radio Part Layouts and Probe Points

Bluetooth Troubleshooting

Bluetooth Schematic

Bluetooth Troubleshooting Setup

Bluetooth Troubleshooting Flowchart

Bluetooth DC and RF Test Points