Nokia 3105 Service Manual 9rh48rf

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CCS Technical Documentation

RH-48 Series Transceivers

Troubleshooting - RF

RH-48

Troubleshooting - RF CCS Technical Documentation

Contents

Page No

RF Troubleshooting ........................................................................................................3

RH-48 General Troubleshooting Notes........................................................................3

Phone Components.......................................................................................................4

Phone Cannot Make a Call.........................................................................................5

Transmitter Troubleshooting........................................................................................6

Low Tx Power............................................................................................................6

Cell Transmitter Setup ...............................................................................................7

Cell Transmitter Path ...............................................................................................10

Tx AGC Tuning.....................................................................................................13

Cell Power Amplifier...............................................................................................14

Cell PMIC ................................................................................................................15

Cell IF/RF AGC and PA Control.............................................................................17

Cell Power Detector .................................................................................................17

Tx System Block Diagram.......................................................................................19

Receiver Troubleshooting...........................................................................................19

Rx IF.........................................................................................................................19

Switching the Gain...................................................................................................24

Rx RF .......................................................................................................................26

Rx AGC (Cell mode)................................................................................................28

Receiver Block Diagram..........................................................................................29

Synthesizer Troubleshooting......................................................................................29

Synthesizer Setup.....................................................................................................30

VCTCXO Tuning.....................................................................................................31

VCTCXO Reference Clock......................................................................................35

UHF Synthesizer......................................................................................................36

Rx VHF....................................................................................................................38

Tx VHF ....................................................................................................................39

Tuning Descriptions....................................................................................................41

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CCS Technical Documentation Troubleshooting - RF

RF Troubleshooting

RH-48 General Troubleshooting Notes

First check the RX AGC PDM value when troubleshooting the receiver. 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 but there is still a problem, check

the actual AGC voltages. RF probing at specific locations in the chain can help to pin-

point the source of the problem.

Likewise, first check the measured output power and AGC values when troubleshooting

the transmitter, which give an indication of where to start probing.

Although the tables in this chapter include power levels for many combinations of AGC

values, it is generally only necessary to check one combination. The additional informa-

tion is provided for use in unexpected situations. Likewise, although probing points and

signal-level information are given for each point in the receiver and transmitter chains, it

is not necessary to probe each point on every phone — only the suspected trouble spots.

Absolute power measurements were made with an Agilent (HP) 85024A active

high-impedance probe. Other probes may be used (make sure the probe is high-imped-

ance so the measurement does not load the circuit), but they may have different gains.

Therefore, adjust the absolute measurements accordingly, especially if you are using a

probe attenuator.

Typically, the higher loss occurs at the band edges where a range is given for loss. Prob-

ing 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 5 dB, straightforward probing on the input and output and then subtracting might not

result in 5 dB because the input impedance could be different from the output imped-

ance. Most components in the RF section have the same input and output impedance

(50ohms). Where this is not the case, absolute power is noted in the tables in dBm rather

than loss or gain in dB.

Inject a CW tone into the receiver when testing the CDMA receiver. The gains and losses

are the same for a CW signal as for the CDMA.

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

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Troubleshooting - RF CCS Technical Documentation

Phone Components

Figures 1 and 2 illustrate the main components of the RH-48.

RF Connector

LCD Module Connector

Figure 1: RH-48 RF components

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CCS Technical Documentation Troubleshooting - RF

Cell Duplexer

Cell Isolator

PA PMIC DC-DC Converter

Cell Tx PA

Battery Converter

YODA Rx DownConverter

Rx IF CDMA Filter

On/Off Switch

Rx IC “Alfred” LNA+Downconverter

Cell Rx RF SAW Filter

Cell Tx SAW Filter

Jedi Tx Up-Converter

VCO

VCTCXO

UPP (B.B)UEM (B.B)

SIM Card Connector

Phone Cannot Make a Call

Verify the following if the phone cannot make a call:

• The phone is in normal mode (i.e., the phone is searching for a signal, net server is on).

• The Preferred Roaming List (PRL) is loaded into the phone.

Flash

Tomahawk Connector

Figure 2: RH-48 RF components

• The phone is tuned and has passed tuning. (Read the tuning parameters using the Batch Tune component in Phoenix; an untuned phone has all zeros in the tuning file.)

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

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Troubleshooting - RF CCS Technical Documentation

• The SID is correct and entered into the phone.

• The MIN and MDN are entered into the phone.

• The VCTCXO is centered as described in the VCTCXO tuning description on page 31.

• The transmitter and receiver are working properly in Local Mode.

Transmitter Troubleshooting

Low Tx Power

Use Phoenix to turn on the transmitter in local mode, and check the following:

1 Verify the current (0.7 - 1A for max power, mode, and channel dependent).

2 Use a microscope to visually inspect the PWB for proper placement, rotation, and

soldering of components.

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

quency:

• If the signal is not on frequency, check in the 100 MHz span.

• If the signal is present but off frequency, check the synthesizer. Most likely, one of the synthesizers is not locked, or the VCO has no output signal.

• If the signal is not present, or is present but low in amplitude, use the probing

tables to determine where in the chain the fault occurs.

4 Verify that the AGC PDMs are set for the desired Tx power as listed in the Tx AGC

Tuning table on page 12, and ensure that the AGC voltages are correct.

5 Check the LOs for proper frequency and amplitude.

6 Ensure that the power supplies to the transmitter have the correct voltage.

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CCS Technical Documentation Troubleshooting - RF

Cell Transmitter Setup

Use the following steps to set up the phone for Tx troubleshooting in Phoenix.

1Open the Phone Control dialog box.

Figure 3: Phone Control dialog box for Tx troubleshooting

2 Click the LOCAL button in the Phone State area to put the phone into Local

Mode.

3 Select the following values on the RF Main Mode dialog box:

• Band = Cell (CDMA)

• Channel = 384

• Mode = Rx/Tx

Figure 4: RF Main Mode dialog box for Tx troubleshooting

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Troubleshooting - RF CCS Technical Documentation

4 Click the Set button.

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

5 Select the Rho ON check box on the CDMA Control dialog box.

Figure 5: CDMA Control dialog box for Tx troubleshooting

6 Click the Execute button.

7 At this point you should be able to measure Tx Pout at the RF connector. The cell

band Tx Pout =0 to 2dBm. If you do not see these values, set the AGC PDM for 25dBm and probe the Tx path to figure out where in the path the fault occurs.

8Open the General I/O dialog box to set the PA gain state.

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CCS Technical Documentation Troubleshooting - RF

9 Enter 10, 13, 12, and 8 in the PIN # fields.

Figure 6: General I/O dialog box for Tx troubleshooting

10 Select the boxes in the Enable column for each pin.

11 Click the Get All button.

12 Ensure that all of the pins have a value of H in the State column. (Click the L val-

ues to change them to H values.)

13 Adjust the following PDM field values on the RF PDM dialog box:

• Tx IF AGC = -280

• Tx RF AGC = -280

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Troubleshooting - RF CCS Technical Documentation

Figure 7: RF PDM dialog box for Tx troubleshooting

14 Ensure that the Phone Tx Pout = +25dBm and the current = 770-860mA.

Cell Transmitter Path

The following table indicates the test points to probe when troubleshooting the cell transmitter path. It is recommended that you follow the steps in order. An HP high frequency probe was used to make the frequency and output power measurements.

Cell Transmitter Test Path

Test Point

T1 Z601 pin1 Jedi-Out -43dBm/

T2 Z601 pin 3 PA-In -25dBm/

T3 N803 pin 8 PA-Out 5.0dBm/

T4 Z803T Iso-Out 2.2dBm/

Part* Function

Typical Value/ Frequency HP85024A

836.52MHz

Typical Value Frequency Prod Probe

-13.2dBm/

836.52MHz

-15.4dBm/

836.52MHz

18.3dBm/

836.52MHz

10.3dBm/

836.52MHz

Comments

Output of Jedi Driver, Input to Tx SAW Filter

Output of Tx SAW, Input to PA

Output of PA, Input to Isolator

Output of Isolator, Input to Duplexer

T5 C603L IF-Out -29dBm/

228.6MHz

T6 C638T, C654T,

C633R, C635R, C603LR

T7 C655R VR7 2.7V dc UHF PLL Supply from UEM

VR5 2.7V dc VHF VCO/PLL, IQ modulator sup-

-24dBm/

228.6MHz

Tx IF Probing Point at IF Filter

ply from UEM

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CCS Technical Documentation Troubleshooting - RF

Cell Transmitter Test Path

Test Point

T8 C636L, C624T,

T9 C605R, C606R VAGC-Tx 0.2 to 1.8V dc Tx AGC Control Voltage from UPP.

T10 C658R, C600T VIO-Tx 1.8V dc Supply for Digital circuits from

T11 C805B, C810T,

T12 C802L, C813L VPA 3.6V dc

T13 C814R C814R 1.8V dc

Part* Function

VR2 2.7V dc Mixer, driver, and IF supply from L609B, C612L, C630B, L607B

VBAT 3.6V dc Battery Voltage C816R

* The R, L, T, and B values at the end of the part names indicate the Right, Left, Top, and Bottom side of the part respectively in Figures 8 and 9.

Typical Value/ Frequency HP85024A

(High Gain)

(Enable)

Typical Value Frequency Prod Probe

Comments

UEM

0.2V = Max Gain

1.8V = Min Gain

UEM

(Nominal Voltage 3.6V dc)

Main PA Supply Voltage from PMIC. Lgain=0.8V, Mgain=-1.25V, Hgain=Vbat

PA Gate Voltage (Enable/Disable) Disable=0V

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Troubleshooting - RF CCS Technical Documentation

Figure 8 shows each testing point from the Cell Transmitter Test Path table for the Jedi TXIC section. Always attach a 20dB pad (11881-60001) when probing with an HP85024A high frequency probe.

Figure 8: (Top) PWB. (Bottom left) A zoomed view of the testing points on the Jedi TXIC section.

(Bottom right) A zoomed view of the Jedi TXIC section with part numbers.

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CCS Technical Documentation Troubleshooting - RF

Figure 9 shows each testing point for the PA section from the Cell Transmitter Test Path table on page 10. Always attach a 20dB pad (11881-60001) when probing with an HP85024A high frequency probe.

Figure 9: (Top) PWB. (Bottom left) A zoomed view of the testing points on the PA section.

Tx AGC Tuning

Tx power versus IF/RF PDM can be verified against FlaLi specification limits. Make sure that the PA is set in high gain mode (GenIO bits 10, 13, and 12 are set to H).

(Bottom right) A zoomed view of the PA section with part numbers.

Tx AGC Tuning

Tx Tuning AGC Step

Tx AGC (0) 308 -46 -55 -37

Tx AGC (1) 130 -24 -34 -14

Tx AGC (2) 85 -15 -25 -6

Tx AGC (3) 51 -4.5 -14 5

Tx AGC (4) 19 2.5 -7 12

Tx AGC (5) -5 6 -3 15

Tx AGC PDM Value

Target Power

Low Limit High Limit

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Troubleshooting - RF CCS Technical Documentation

Tx AGC Tuning

Tx Tuning AGC Step

Tx AGC (6) -94 15 6 24

Tx AGC (7)* -280* 25 21 27

Cell Power Amplifier

The power amplifier (PA) has the DC/DC converter (PMIC device), which controls the transmitter. The following tables show the circuits that have an effect on the transmitter path and how to troubleshoot them.

PA Power and Gain Specifications

Mode Name

Tx AGC PDM Value

PA Power and Gain Measurements

Power Amplifier Input

Test Point

pin3-Z601 left-R814

Power Output Range

Target Power

Low Limit High Limit

Power Amplifier Output Test Point

Nominal Gain

Vcc Range

Vcc Test Point

Gain mode 0 V0 up to 6 23.8 0.75- 0.88 C806

Gain mode 1 V1 6 to 11 25.2 1.125- 1.375 C806

Gain mode 3 V2 Not used Not used 2 - 2.5 C806

Gain mode 2 Bypass 11 up 29 3 - 4 C806

Overall Gain V0 to

Bypass

unit N/A dBm dB VDC N/A

Phoenix Control and Example Values

PA Gain Step

Gen IO 12 GenIO13

LL0.8V0

H L 1.2 V1

L H 2.2 V2

HH3.7Bypass

63.5 to 7.3 +/- 0.5

PA Vcc volt (v)

Spec Name

*Not an actual FlaLi tuning PDM. PDM to produce approximately 25dBm at antenna connector.

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CCS Technical Documentation Troubleshooting - RF

Cell PMIC

The following tables show the PMIC troubleshooting information.

PMIC Setup: Mode

LocalOnOnCELL

PMIC Measurements:

Tx Rx Band

Pin Label Test Point Units

1 EP Pin 1 1.8 UPP IC enable = GenIO 10

2 M0 Pin 2 1.8 UPP Control 0 = GenIO 12

3 M1 Pin 3 1.8 UPP Control 1 = GenIO 13

4NCNCNCNCNC

5 FB Pin 5 0.75 - 4 M0, M1 See PA worksheet. Output to fly-

6 FB Pin 6 0.75 - 4 M0, M1 Shares PWB pad with pin 5

7 BYPVout bottom-

C808

8 VDD right-L810 VBATT VBATT Digital DC supply, shared with

9 VSS GND GND GND Digital GND, shared gnd with

10 NC NC NC NC NC

11 Vbgap NC NC NC Bandgap voltage output

0.75 - 4 M0, M1 PMIC bypass output used at

Depends on

Comments

back inductor.

Pout > 12 dBm

pin 12, 14, 15

pin 13

12 VDD right-L810 VBATT VBATT Digital DC supply

13 Vss GND GND GND Digital GND, shared gnd with

pin 9

14 Vsw right-L810 VBATT VBATT Switcher supply

15 Vsw right-L810 VBATT VBATT Switcher supply

16 Gsw GND GND GND Switcher GND, does not share

with pin 9 and pin 13

Good phone PMIC Resistances

Pin Resistance

160k

275k

380k

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Troubleshooting - RF CCS Technical Documentation

Good phone PMIC Resistances

Pin Resistance

4 1.59M

51.6M

62M

72M

82M

90.1

10 100

11 11 5 k

12 60k

13 0.2

14 1.3M

15 1.18M

16 0.1

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CCS Technical Documentation Troubleshooting - RF

Cell IF/RF AGC and PA Control

The following Cell CDMA Channel 384 (Skyworks PA) table illustrates the PDM values and their typical values for the IF AGC, RF AGC Jedi Pout, gain steps, and the PA VCC levels. This table also shows the typical power output at the RF connector.

Cell CDMA Channel 384 (Skyworks PA)

Tx RF AGC Tx IF AGC Jedi Po

PDM

-290 0.45 Bot-

-196 0.59 -196 0.59 -2 H H 3.61 28 20

-95 0.75 -95 0.75 -9.2 H H 3.67 28 13.2

-95 0.75 -95 0.75 -9.2 H L 1.2 26 11

-48 0.83 -48 0.83 -13 H L 1.2 25.8 7

-48 0.83 -48 0.83 -13 L L 0.82 24.5 6

17 0.93 17 0.93 -19 L L 0.82 0

80 1.04 80 1.04 -29 L L 0.82 -10

120 1.11 120 1.11 -39 L L 0.82 -20

168 1.19 168 1.19 -49 L L 0.82 -30

249 1.32 249 1.32 -59 L L 0.82 -40

Typical Value

Test Point

tom C606

PDM

-290 0.45 Top

Typical Value

Test Point

C605

Typical Value

3pin 1

Test Point

Z601

PA Gain

Step

Gen

Gen IO 13

Typical Value

IO 12

H H 3.47 C806 DM 25

PA Vcc

Test Point

PA Gain

Conn RF Pout

324 1.49 324 1.49 -69 L L 0.82 -50

Cell Power Detector

The following tables illustrate the measurements required for troubleshooting the cell power detector.

Cell Power Setup:

Mode Tx Rx Band Chnn Rho

Local On On CELL 384 On

Input Chnn Tx Freq Rx Freq

384 836.52 881.52

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Troubleshooting - RF CCS Technical Documentation

Cell Power Measurements:

Cell, Channel 384

Tx ADC

RF/IF pdm

324 L L -50 -86.3 right

142 L L -25 -63 2 235

17 L L 0 -41 1.998 235

-48 L L 6 -30 1.967 250

-48 H L 7 -29 1.957 268

-95 H L 11 -26 1.93 286

-95 H H 13.2 -23.5 1.9 435

-146 H H 17 -21.5 1.86 486

-178 H H 19 -19 1.812 550

-214 H H 21 -17 1.745 630

PA Gain Step

GIO 12GIO

Conn RF Pout

Power Detector Comments

Pout at detector

Test Point

R814

Det Out

2left

Test Point

C807

235 CELL band and

Det=Detector Po=Power

detector coupling is about 22 dB

-252 H H 23 -15 1.667 730

-290 H H 25 -12 1.547 860

-316 H H 26 -11.5 1.485 950

-328 H H 26.5 -11 1.44 1000

-351 H H 27.5 -10 1.36 1095

none dBm dBm/

30kHz

Detector Reference and DC Supply

Label Test Point Typical Value

Det Ref left-C803 2

Det Supply bottom-C257 2.8

VDC dBm only

VDC

refers to total power measured

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CCS Technical Documentation Troubleshooting - RF

Tx System Block Diagram

Figure 10 illustrates a simplified block diagram of the transmitter. The figure shows every major component from I and Q baseband to the antenna port.

Note: See the Schematics chapter for an RH-48 transmitter schematic.

Receiver Troubleshooting

Rx IF

Use Phoenix to perform the following steps for troubleshooting the receiver. Together with the VCO frequency and level verification, this test should be the first test for a nonworking receiver. This test verifies the entire receiver chain, from input connector to baseband output.

1 Inject a CW signal 881.82MHz or 881.22MHz (CH-384 offset by 300KHz) at a

fixed –75dBm power level. If you do not have a signal generator, use the CALL BOX in AMPS mode on Channel 374 or 394 (10 channels away from channel 384).

Figure 10: Tx system block diagram

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Troubleshooting - RF CCS Technical Documentation

2Open the Phone Control dialog box..

Figure 11: Phone Control dialog box for Rx IF troubleshooting

3 Click the LOCAL button in the Phone State area to put the phone into Local

Mode.

4 Select the following values on the RF Main Mode dialog box:

• Band = Cell (CDMA)

• Channel = 384

• Mode = Rx

Figure 12: RF Main Mode dialog box for Rx IF troubleshooting

5 Click the Set button.

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

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CCS Technical Documentation Troubleshooting - RF

6 Use a spectrum analyzer to test TP3 (I+,I-, Q+, Q-). Set the S.A to 300KHz center

frequency, 200KHz SPAN, and +10dBm reference level. The spectrum analyzer should read –8dBm without any settings to the PDM.

Use the following CDMA Generator Code Domain Setup table to configure the CDMA generator code domain.

CDMA Generator Code Domain Setup

Channel Power

Pilot -7dB 0

Paging -12dB 1

Traffic -15.6dB 10

Sync -16dB 32

The following Rx IF Troubleshooting table shows the steps for Rx IF troubleshooting.

Rx IF Troubleshooting

Typical Value/

Step # Part* Function

TP1 L702R IF-IN +1.3 dBm/

TP2 L701L/R SAW Out -16 dBm/

Frequency HP85024A

183.6MHz

Walsh code

Typical Value Frequency Prod Probe

-12/-27 dBm

183.6MHz

-35/-50 dBm

183.6MHz

Comments

I.F Input to Z701 (I.F filter).

NOT 50 ohm

Differential outputs of Z701.

NOT 50 ohm

TP3 I+, I-, Q+, Q- I/Q out-

puts of Yoda N700

TP4 C728T 19.2MHz In+6.5 dBm

TP5 C711T 19.2MHz

Out

TP6 L708R (L708R

for Prod Probe)

TP7 C731T VREF 1.35Vdc System reference voltage

TP8 R702L (C703R) RX_IF_AGC 0.2 to 1.8 Vdc AGC control Voltage. 0.2V =

VHF VCO +1.0 dBm

300KHz tone for input:

881.22MHz

19.2MHz

+4 dBm

19.2MHz

367.2MHz

-69/-84 dBm 300KHz

-22 dBm

19.2MHz

-25 dBm

19.2MHz

-61 dBm

367.2MHz

Baseband differential outputs of the IF IC (N700). To test: set the input to 881.22 or 881.82MHz/

-75dBm to get a 300KHz tone when receiver is on channel 384 (881.52MHz)

Sine wave input to N700 from VCTCXO.

Square wave output of N700 to baseband.

Rx VHF VCO - Fixed at

367.2MHz (Be careful not to load the circuit with the probe.)

1.35Vdc from UEM.

Max Gain, 1.8V = Minimum Gain

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Troubleshooting - RF CCS Technical Documentation

Rx IF Troubleshooting

Typical Value/

Step # Part* Function

TP9 R703T (R701L,

R715T)

TP10 C734B VR3 2.7Vdc VCTCXO buffer supply from

TP11 C712R, C744R VR6 2.7Vdc Main supply to N700, from UEM.

TP12 C710T, C704B VIO 1.8Vdc Digital circuits supply from

* The R, L, T, and B values at the end of the part numbers indicate the Right, Left, Top, and Bottom side of the part respectively in Figure 13.

VR7 2.7Vdc VHF VCO Supply from UEM

Frequency HP85024A

Typical Value Frequency Prod Probe

Comments

UEM.

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CCS Technical Documentation Troubleshooting - RF

Figure 13 shows each testing point from the Rx IF Troubleshooting table for the Rx IF section.

Figure 13: (Top) PWB. (Bottom left) A zoomed view of the testing points on the Rx IF section.

(Bottom right) A zoomed view of the Rx IF section with part numbers.

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Troubleshooting - RF CCS Technical Documentation

Switching the Gain

Use the following steps if the receiver is not working properly and you need to switch the Rx gain state.

1Open the Phone Control dialog box.

Figure 14: Phone Control dialog box for switching the Rx gain state

2 Click the LOCAL button in the Phone State area to put the phone into Local

Mode.

3 Select the following values on the RF Main Mode dialog box:

• Band = Cell (CDMA)

• Channel = 384

• Mode = Rx

Figure 15: RF Main Mode dialog box for switching the Rx gain state

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CCS Technical Documentation Troubleshooting - RF

4 Click the Set button.

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

5 Connect a signal generator in CW mode (881.52MHz, -25dBm) to the RF connec-

tor. If you do not have a generator, use the Call Box Amps Mode RF Generator, Channel 384, -25dBm and set the FM modulation to 100Hz, deviation 400Hz.

6 To switch the Rx gain states, open the RF Register R/W dialog box. Two gain

states (Hi and Lo) are available in the receiver.

High Gain State

Figure 16: RF Register R/W dialog box for switching Rx gain states

7 Select the RF register: Yoda Register #6 and select the appropriate gain states.

The following values apply:

• Bit 0=1, means a Hi gain state.

• Bit 0=0, means a Lo gain state.

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Troubleshooting - RF CCS Technical Documentation

Rx RF

The following Rx RF Troubleshooting table indicates the test points to probe when troubleshooting the Rx RF. It is recommended that you follow the steps in order.

Rx RF Troubleshooting

Typical Value/

Step # Part* Function

R1 L802R (Top

side of the PWB)

R2 L906L LNA-In -35dBm/

R3 C903L LNA-Out -13/-31dBm

R4 Z901-R-Bot-

tom, N901Pin16

R5 C906R Mixer-

R6 C912B/R914R IF Output

R7 R912B/R911L L.O Input

RF-IN -25dBm/

RF Filter Output Mixer-In

out

to N700

to N901

Frequency HP85024A

881.52MHz

-18/-35dBm

881.52MHz

-5/-21dBm

183.6 MHz

+1.5/-15dBm

183.6MHz

-2.5dBm

1065.12MHz

Typical Value Frequency Prod Probe

-42dBm

881.52MHz

-42dBm

881.52MHz

-29/-45dBm

881.52MHz

-30/-45dBm

881.52MHz

-23/-38dBm

183.6MHz

-12/-29dBm

183.6MHz

-18dBm

1065.12MHz

Comments

Input Connector reference level

Test Duplexer insertion Loss (Without DC Block)

Test LNA gain ~ 13dB

Test RF Filter Insertion loss (Without DC Block)

Test Output on Downconverter on N901

Test Alfred output to Yoda IF-IC (N700)

Test VCO output to Alfred (N901) Levels are for Channel 384

R8 R9056T, L909L,

L901T, R910B

R9 R902B Rx-SW1 H.G = 2.7V

* The R, L, T, and B values at the end of the part names indicate the Right, Left, Top, and Bottom side of the part respectively in Figure 17.

VR4 2.7V dc Power supply to Alfred (N901)

L.G = 0V

LNA gain control, on the Alfred side, High Gain > 2.5V dc

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CCS Technical Documentation Troubleshooting - RF

Figure 17 shows the Rx RF testing points from the Rx RF Troubleshooting table.

Antennae Connector (other side)

Figure 17: (Top left) PWB. (Top right) The antenna connector on the opposite side of the PWB, (Bottom left) A zoomed view of the testing points on the Rx RF section. (Bottom right) A zoomed view of the Rx RF section

with part numbers.

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Troubleshooting - RF CCS Technical Documentation

Rx AGC (Cell mode)

The following Rx RF AGC PDM vs AGC Voltage table shows the Rx RF AGC PDM vs AGC voltages in local mode on channel 384.

Rx RF AGC PDM vs AGC Voltage

Rx RF AGC

PDM

-512 0.08 right R702

-400 0.260

-300 0.436

-200 0.597

-100 0.753

00.913

100 1.076

200 1.24

300 1.403

350 1.494

400 1.570

500 1.740

511 1.761

Typical Value

Test Point

UNITS VDC

Rx AGC vs RF Pin for CELL Band

Conn RF Pin

-25 1.492

-35 1.298

-45 1.159 In Normal mode, the phone will adjust RF RX

-55 1.019 Rx power is coming in, the I and Q will be about

-65 0.861

-75 0.705 Approximately 1pdm per 1mV

-85 0.530

-92 0.425

CELL RF AGC

Comments

AGC

0.5Vpp and 1.3V

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CCS Technical Documentation Troubleshooting - RF

Rx AGC vs RF Pin for CELL Band

Conn RF Pin

-95 0..633 Note the reduced delta because the LNA is

-100 0.594

-105 0.524

-107 0.470

UNITS VDC

Receiver Block Diagram

Figure 18 illustrates a simplified block diagram of the receiver. The diagram shows every major component from the antenna port to the I and Q baseband.

Note: See the Schematics chapter for an RH-48 receiver schematic.

CELL RF AGC

Comments

switched on

Figure 18: Receiver block diagram

Synthesizer Troubleshooting

Faulty synthesizers can cause both Rx and Tx failures during tuning, in addition to the VCTCXO tuning. The following synthesizers are incorporated into the RH-48:

• UHF (cell) PLL inside Jedi IC (N601)

• Tx VHF (457.2MHz) with PLL in Jedi IC

• Rx VHF (367.2MHz) with PLL in Yoda IC

RH-48

Troubleshooting - RF CCS Technical Documentation

Synthesizer Setup

Use the following steps to set up the phone for Tx troubleshooting in Phoenix.

1Open the Phone Control dialog box.

Figure 19: Phone Control dialog box for Tx troubleshooting

2 Click the LOCAL button in the Phone State area to put the phone into Local

Mode.

3 Use the following settings for the Band, Channel, and Mode fields on the RF

Main Mode dialog box:

• UHF: Use the Rx/Tx mode in Cell band. This allows you to check power in both the Rx and Tx circuits.

• Rx VHF: Use the Rx mode. One band is enough.

• Tx VHF: Use the Rx/Tx mode in Cell band.

Figure 20: RF Main Mode dialog box for synthesizer troubleshooting

RH-48

CCS Technical Documentation Troubleshooting - RF

4 Click the Set button.

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

5 Read register templates Jedi(0) bits 10 and 11 for the UHF and Tx VHF lock condi-

tion on the RF Register R/W dialog box.

6 Read register templates Yoda(0) bit 11 for the RX VHF lock condition.

VCTCXO Tuning

The VCTCXO can be manually tuned to verify failed tuned phones, or to verify if a phone cannot make a call. This can be done with the phone in Local Mode and generating a CW signal. The frequency accuracy of the VCTCXO can be measured using an HP8960 callbox in AMPS mode, an HP4406 Tx tester, or a spectrum analyzer (preferably using a lab system 10MHz source as equipment reference). Replace the VCTCXO if the VCTCXO AFC DAC value does not meet the tuning requirements after tuning.

Figure 21: RF Register R/W dialog box for synthesizer setup

RH-48

Troubleshooting - RF CCS Technical Documentation

Use the following steps to manually tune the VCTCXO:

1Open the Phone Control dialog box.

Figure 22: Phone Control dialog box for VCTCXO troubleshooting

2 Click the LOCAL button in the Phone State area to put the phone into Local

Mode.

3 Select the following values on the RF Main Mode dialog box:

• Band = Cell (CDMA)

• Channel = 384

• Mode = Rx/Tx

Figure 23: RF Main Mode dialog box for VCTCXO troubleshooting

4 Do not use CDMA control to turn on Rho.

5Open the BB General I/O dialog box to set the CW signal.

RH-48

CCS Technical Documentation Troubleshooting - RF

6 Type 10, 13, 12, and 8 in the fields in the PIN # column.

Figure 24: General I/O dialog box for VCTCXO tuning

7 Click the Get All button.

8 Change the value for Pin 8 in the Source column to GenIO Output.

9 Ensure that all of the pins have a value of H in the State column. (Click the L val-

ues to change them to H values.)

10 If using an HP4406 or a spectrum analyzer to measure the signal, set the center

frequency to 836.52MHz and the span to 2MHz. Establish a marker at

836.52MHz.

11 If using an HP8960 to measure the frequency accuracy, set the callbox state to

AMPS and set the channel to 384. Use the frequency accuracy measurement to center VCTCXO.

RH-48

Troubleshooting - RF CCS Technical Documentation

12 Adjust the AFC value to center the VCTCXO on the RF PDM dialog box. The tun-

ing range is approximately +/- 10kHz.

Figure 25: Manually adjusting the AFC to center VCTCXO

13 Adjust the AFC value so that the output signal is within +/- 100Hz. If you are

using an HP4406 or a spectrum analyzer, narrow the span to 1kHz or less.

RH-48

CCS Technical Documentation Troubleshooting - RF

VCTCXO Reference Clock

Figure 26 shows the 19.2 MHz VCTCXO reference clock.

Figure 26: (Top) PWB. (Bottom left) A zoomed view of the testing points on the 19.2 MHz VCTCXO reference

clock. (Bottom right) A zoomed view of the 19.2 MHz VCTCXO reference clock with part numbers.

RH-48

Troubleshooting - RF CCS Technical Documentation

Figure 27 shows the synthesizer block diagram.

Note: See the Schematics chapter for an RH-48 synthesizer schematic.

UHF Synthesizer

Following are possible causes for an incorrect UHF frequency:

• Power supplies to Jedi PLL (N601) are missing or low (VR7)

• Loop filter components are missing or incorrectly installed

• Matching components to Jedi TxLO/PLL input are missing or incorrectly installed

• 19.2MHz reference clock is missing or low

• Programming is incorrect

• Component failure (VCO or PLL portion of Jedi)

Figure 27: Synthesizer block diagram

RH-48

CCS Technical Documentation Troubleshooting - RF

Figures 28 and 29 show the UHF synthesizer layout.

Figure 28: (Top) PWB. (Bottom left) A zoomed view of the testing points on the UHF synthesizer layout.

(Bottom right) A zoomed view of the UHF synthesizer layout with part numbers.

RH-48

Troubleshooting - RF CCS Technical Documentation

Figure 29: (Top) PWB. (Bottom left) A zoomed view of the Jedi LO/PLL input match components on the UHF

synthesizer layout (Bottom right) A zoomed view of the Jedi LO/PLL input match components UHF synthesizer

layout with part numbers.

Rx VHF

Following are possible causes for an incorrect Rx VHF frequency:

• Power supplies to the PLL portion of Yoda IC (N700) are missing or low (VR7)

• Loop filter or resonator components are missing or incorrectly installed

• 19.2MHz reference clock is missing or low (C512)

• Programming is incorrect

• Component failure (PLL IC)

Note: See the Schematics chapter for an Rx VHF schematic.

RH-48

CCS Technical Documentation Troubleshooting - RF

Figure 30 shows the layout for the Rx VHF.

Figure 30: (Top) PWB. (Bottom left) A zoomed view of the testing points on the Rx VHF section.

(Bottom right) A zoomed view of the Rx VHF section with part numbers.

Tx VHF

Following are possible causes for an incorrect Tx VHF frequency:

• Power supplies to the PLL portion of Jedi IC (N601) missing or low (VR5)

• Loop filter or resonator components are missing or incorrectly installed

• 19.2MHz reference clock is missing or low (C510)

• Programming is incorrect

• Component failure (Jedi IC)

Note: See the Schematics chapter for a Tx VHF schematic.

RH-48

Troubleshooting - RF CCS Technical Documentation

Figure 31 shows the layout for the Tx VHF.

Figure 31: (Top) PWB. (Bottom left) A zoomed view of the testing points on the Tx VHF section.

(Bottom right) A zoomed view of the Tx VHF section with part numbers.

RH-48

CCS Technical Documentation Troubleshooting - RF

Tuning Descriptions

Tuning Title Description Troubleshooting

Tx Detector This is one of the phone's self-tests

which gives either a pass or fail result only. The phone transmits at several power levels and checks the ADC value of the power detector. The ADC value is measured first for a set of AGC values, then each AGC value is changed one at a time to make sure that the ADC changes as each AGC is changed individually.

Cell PA Temp This is one of the phone's self tunings,

which reads the ADC voltage of a thermistor R821, and checks to make sure the phone is at room temperature. The reason for this is that a phone should not be tuned while it is hot or cold.

Check the AGC voltages and components of the associated PDMs. For problems with the IF or RF AGC, also check Jedi and supporting components. For PA AGC problems, also check the PA and supporting components. If all of the above cases fail, troubleshoot the Tx chain. If all the output powers are passing, then perhaps the test is failing because the ADC voltage is wrong (which at this point we cannot read, so we are measuring the actual output power). If the voltages are wrong, then check the power detector at N805, C803, C807, and also Jedi. If the voltages are correct and it still fails, check the UEM ( D200).

If the phone was recently transmitting in Cell band at full power for an extended period of time, it is probably hot for that reason. Let it cool down for a few minutes, then try again. If it still fails, there may either be a short on the board or else a problem with the PA Temp circuitry. To check PA Temp circuitry, check R821 and D200. If a short is suspected, check the cell PA first. If an infrared camera is available, this is one of the easiest methods to detect a short.

Cell Rx DC Offset I (or Q)

Tx Start-up Current This test turns on the transmitter and

Tx Start-up Amplitude This test turns on the transmitter and

This is one of the phone's self tunings, which measures and adjusts the cell band CDMA receiver DC offsets until they are within the limits.

measures current of the whole phone, which can detect some assembly errors.

checks for the presence of a Tx signal with an amplitude within a specified range. A wide range is allowed since the transmitter is not yet tuned.

Check Yoda (N701) and supporting components.

If current is very high, there may be a short circuit on the phone caused by a solder bridge, a failed component that is internally shorted, a component placed with the wrong rotation which shorts two nodes that should not be, or some other reason. A visual inspection can find solder bridges or wrong component rotations. A failed component can be found by functional tests of the phone's sub-blocks.

Check proper placement, rotation, and soldering of the components in the Tx chain. Check for the presence of LO tones. Check for the presence of a Tx signal at each point in the Tx chain.

RH-48

Troubleshooting - RF CCS Technical Documentation

Tuning Title Description Troubleshooting

VCTCXO Frequency The purpose of this tuning is to deter-

mine what the AFC DAC value needs to be in order to center the VCTCXO frequency. The transmitter is turned on and no Tx baseband modulation is provided. The carrier is then centered in frequency. This is done to the carrier after it has been mixed up to 836.52MHz, since it's easier to measure the tolerance of 1ppm at 836.52MHz than it is at 19.2MHz. Additionally, the tone at 836.52MHz can be measured without taking the phone apart.

1) If there is no tone, probe pin 3 of G501 for a tone at 19.2 MHz. If this is not present, check power supplies, particularly ensure

2.7v on VCTCXO Vcc pin, pin 4 of G501. Also check the control pin, pin 1 of G501, for a voltage between 0.4 and 2.7v. If the voltages are correct, and soldering of all G501 terminals is correct, replace G501. If

19.2 MHz tone is present but tone at

836.52 MHz is not, troubleshoot cell Tx chain.

2) If the carrier is present but the PDM needed to center it is outside of the +/- 150 range, or if it cannot be centered, there is a hardware problem.

3) In the following procedure, performing frequency centering on the RF carrier at

836.52MHz will detect frequency errors due to the VCTCXO and supporting hardware, which will account for the majority of the problems, but will not detect frequency errors due to the hardware that mixes the VCTCXO tone at 19.2MHz up to 836.52MHz. In order to troubleshoot this hardware, frequency centering should be performed on the 19.2MHz tone to +/- 19.2Hz on pin 3 of G501 using a frequency counter, then the VHF and UHF LOs should be checked. Because this will be time-consuming and will probably only account for a small percentage of the failures, it is not recommended unless the situation justifies the time spent. The VHF LO is inside the Jedi IC (N601) and troubleshooting of the cell UHF LO is required.

4) If the carrier can be centered but the PDM is out of range, check the control voltage on pin 1 of G501. If it is 2.2v, (and pin 4 is at 2.7v, and pin 2 at 0v), then the VCTCXO (G501) is working correctly but the circuit that delivers the control voltage is not. Check soldering of all G501 terminals, also check R510, R511, C503, and D200. If the control voltage on pin 1 of G501 is not

2.2v, but the carrier is centered, then there is a problem with the VCTCXO G501. If there is 2.7v on pin 4 and the soldering is correct, then replace G501.

RH-48

CCS Technical Documentation Troubleshooting - RF

Tuning Title Description Troubleshooting

5) If the carrier cannot be centered, check to see if you can adjust to 2.2v on pin 1 of G501. If you can, within the PDM range of +/- 150, then the circuitry that delivers the voltage is working correctly, and the VCTCXO has a problem. Troubleshoot it as described in the previous section. If you cannot adjust to 2.2v within the accepted range, then the AFC circuitry has a problem. Troubleshoot it as described in the previous section.

6) If there is a fault with both the AFC circuitry and the VCTCXO, then several combinations of the previously described conditions are possible. Start by ensuring

2.2v on pin 1 of G501 using a PDM within the range +/- 150, then center the tone.

PA Gain Cell Po(0)Po(3)

Tx AGC This tuning characterizes the AGC curve

These tunings model the cell PA gain curve by setting the PA AGC PDM to several values and measuring output power. First, the Tx PA AGC and the Tx RF AGC are set to (approximately) their maximum used values (not the maximum possible values, but the maximum of the range over which they are used). Then the Tx IF AGC is set so that the transmit power on the antenna connector is approximately +11dBm (this power is reported in the next tuning). Then, six PDM values are written to the PA AGC and the output power is measured for each. These values are reported in this tuning. The software then performs curve fitting to interpolate between the measured data points.

by entering PDM values to the RF AGC and measuring the output power.

If the power readings are low, check the AGC voltages. You can also probe on the PA input to find out if the power level is low going into the PA, or if the power level is correct going into the PA but the PA gain is too low. If the power level going into the PA is too low, probe the Tx chain at all the other points prior to the PA listed in the table to see where the gain is lacking. When that point is identified, check the soldering of all related components, and replace components until the fault is found. If the power on the PA input is not low and the PA AGC voltage is correct, similarly probe the power at all points after the PA to find the fault, being extremely careful not to short the probing point to ground because this will instantly destroy the PA. Visually check soldering first, and probe on PA output as a last resort.

Check Jedi (N601). Also check D400, which generates the PDM signals. Check AGC PDM voltages. Troubleshoot the rest of the cell transmitter if needed.

RH-48

Troubleshooting - RF CCS Technical Documentation

Tuning Title Description Troubleshooting

Tx Gain Comp This tuning ensures that the value of

TxdBCtr correctly corresponds to the absolute Tx output power. On the mid channel, with TxdBCtr set to a specified value, G_Offset is adjusted so that the output power is -8dBm, and that value of G-Offset is recorded (which is an absolute value) in the next tuning. The output power in dBm is recorded in this tuning.

TN G_Offset See description of previous tuning. This

step reports G_Offset.

Tx Limiting Cell This tuning provides an upper limit on

the transmit power while in Cell IS95 mode. The reason for this is to ensure that the phone never goes above the maximum transmit power level. After this is done on the mid channel, the channel is changed to each of the other channels, and detector offset is reported.

Set the phone to local mode and program it to Cellular CDMA Rx/Tx mode on channel 384, using the Main Mode window. Using the Phoenix RF Tuning window, choose mode = RF Tuning, and choose this test. Adjust G_Offset in the "Values” dialog box line until the Tx output power (measured on the RF connector with a spectrum analyzer) is equal to -8.0dBm +/- 0.5dB. Use the G_Offset limit range as a guide to which values to enter.

If G_Offset is not within the limits, troubleshoot the Cell Tx.

If the maximum cannot be reached, either a component in the transmitter has too much loss, or not enough gain. Troubleshoot the transmitter, with the phone set to the same channel as the failed channel. Once this is done on the center channel, change to each of the other channels, and record the power. Do not adjust G_Offset on the other channels, just record the power. It should be within the limits listed in the tuning results file.

Channel Cell Power

Low 1013 22.86-23.06 LowMid 125 23.61-23.81 MidLow 225 24.16-24.36 Mid 384 25.03-25.23 MidHigh 558 24.83-25.03 HighMid 750 24.60-24.80 High 777 24.57-24.77

Rx IF AGC Rx dB Ctr This tuning calibrates the Rx IF AGC

curve. The tuner injects three known signal power levels into the phone's receiver, and for each one the phone's AGC algorithms, adjusts the RX_IF_AGC to get the same amplitude at the output of Yoda, although different amplitudes are going in. From these three points, curve fitting is used to interpolate between measurement points.

LNA Gain This tuning records RxdBCtr (which is

automatically adjusted to produce the same amplitude on the receiver output no matter what the input is) for the receiver with the LNA in high gain mode, and again with the LNA in low gain mode.

While injecting a signal into the receiver, check the values of RX_IF_AGC PDM value and, if needed, voltage. RSSI should be within +/- 2 dB of the actual power in dBm on the RF connector. The AGC will try to keep the same amplitude on Yoda output; therefore, if the AGC value is larger than normal, then the AGC is compensating for loss in the chain prior to the variable gain amplifier.

Check Alfred and supporting components.

Nokia 3105 Service Manual 9rh48rf

Specifications and Main Features

Frequently Asked Questions

User Manual

Troubleshooting - RF

RF Troubleshooting

RH-48 General Troubleshooting Notes

Phone Components

Phone Cannot Make a Call

Transmitter Troubleshooting

Low Tx Power

Cell Transmitter Setup

Cell Transmitter Path

Tx AGC Tuning

Cell Power Amplifier

Cell PMIC

Cell IF/RF AGC and PA Control

Cell Power Detector

Tx System Block Diagram

Receiver Troubleshooting

Rx IF

Switching the Gain

Rx RF

Rx AGC (Cell mode)

Receiver Block Diagram

Synthesizer Troubleshooting

Synthesizer Setup

VCTCXO Tuning

VCTCXO Reference Clock

UHF Synthesizer

Rx VHF

Tx VHF

Tuning Descriptions