Nokia 2118 Service Manual 09rh77rf

Nokia Customer Care

2118 (RH-77)

Mobile Terminal

RF Description and

Troubleshooting

2118 (RH-77) RF Description and Troubleshooting Nokia Customer Care

Contents Page

Components ..................................................................................................................................................... 3

Transmitter Troubleshooting ....................................................................................................................... 5

Low Tx Power ................................................................................................................................................ 5

Cell Transmitter Setup ...............................................................................................................................5

Cell Transmitter Path ..................................................................................................................................8

Tx AGC Tuning ........................................................................................................................................ 11

Cell Power Amplifier ............................................................................................................................. 12

Cell PMIC.................................................................................................................................................. 12

Cell IF/RF AGC and PA Control........................................................................................................... 14

Cell Power Detector .............................................................................................................................. 16

Tx System Block Diagram ........................................................................................................................18

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

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

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

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

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

Receiver Block Diagram ...........................................................................................................................30

Synthesizer Troubleshooting .................................................................................................................... 31

Synthesizer Setup ......................................................................................................................................31

VCTCXO Tuning ...........................................................................................................................................33

VCTCXO Reference Clock ..................................................................................................................... 36

Synthesizer Block Diagram .....................................................................................................................37

UHF Synthesizer .........................................................................................................................................38

Rx VHF ..........................................................................................................................................................39

Tx VHF ...........................................................................................................................................................40

2118 (RH-77)

Nokia Customer Care RF Description and Troubleshooting

Components

Figure 1 and Figure 2 illustrate the main components of the 2118.

RF connector LCD module connector

Figure 1: RF components (top)

2118 (RH-77) RF Description and Troubleshooting Nokia Customer Care

Cell duplexer

Cell isolator

PA PMIC DC-DC converter

Cell Tx PA

Battery converter

Rx downconverter

Rx IF CDMA filter

UEM

On/Off switch

Rx IC LNA+downconverter

Cell Rx RF SAW filter

Cell Tx SAW filter

Tx Up-Converter

VCO

VCTCXO

UPP

SIM card connector

Flash

Pop-port connector

Figure 2: RF components (bottom)

2118 (RH-77)

Nokia Customer Care RF Description and Troubleshooting

Transmitter Troubleshooting

Low Tx Power

Use Phoenix to turn on the transmitter in Local Mode, and check the following:

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

• Use a microscope to visually inspect the PWB for proper placement, rotation, and soldering of components.

• Look for the presence of a Tx signal on the spectrum analyzer at the correct frequency:

• 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.

• Verify that the AGC PDMs are set for the desired Tx power as listed in the Tx AGC Tuning table on page 11, and ensure that the AGC voltages are correct.

• Check the synthesizers for proper frequency and amplitude.

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

Cell Transmitter Setup

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

1. Open the Phone Control dialog box.

Figure 3: Phone Control dialog box for Tx troubleshooting

2118 (RH-77) RF Description and Troubleshooting Nokia Customer Care

2. Click the LOCAL button in the Phone State area to put the mobile terminal 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

4. Click Set.

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 Execute.

7. At this point you should be able to measure Tx Pout at the RF connector. The cell band Tx Pout =0 to 2 dBm. If you do not see these values, set the AGC PDM for 25 dBm and probe the Tx path to figure out where in the path the fault occurs.

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

2118 (RH-77)

Nokia Customer Care RF Description and Troubleshooting

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 values 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

2118 (RH-77) RF Description and Troubleshooting Nokia Customer Care

Figure 7: RF PDM dialog box for Tx troubleshooting

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

Cell Transmitter Path

Table 1 indicates the test points (see Figure 8) 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

Table 1: Cell Transmitter Test Points

Typical Test Point

T1 Z601 pin1 N601-Out -43 dBm/

T2 Z601 pin 3 PA-In -25 dBm/

T3 N803 pin 8 PA-Out 5.0 dBm/

Part* Function

Value/

Frequency

HP85024A

836.52 MHz

Typical Value Frequency Prod Probe

-13.2 dBm/

836.52 MHz

-15.4 dBm/

836.52 MHz

18.3 dBm/

836.52 MHz

Comments

Output of N601 Driver, Input to Tx SAW Filter

Output of Tx SAW, Input to PA

Output of PA, Input to Isolator

T4 Z803T Iso-Out 2.2 dBm/

836.52 MHz

T5 C603L IF-Out -29 dBm/

228.6 MHz

T6 C638T, C654T,

C633R, C635R, C603LR

T7 C655R VR7 2.7 V dc UHF PLL Supply from UEM

VR5 2.7 V dc VHF VCO/PLL, IQ modulator

10.3 dBm/

836.52 MHz

-24 dBm/

228.6 MHz

Output of Isolator, Input to Duplexer

Tx IF Probing Point at IF Filter

supply from UEM

2118 (RH-77)

Nokia Customer Care RF Description and Troubleshooting

Table 1: Cell Transmitter Test Points (Continued)

Typical Test Point

Part* Function

Value/

Frequency

HP85024A

T8 C636L, C624T,

L609B, C612L, C630B, L607B

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

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

T11 C805B, C810T,

C816R

T12 C802L, C813L VPA 3.6 V dc

T13 C814R VG 1.8 V dc

VR2 2.7 V dc Mixer, driver, and IF supply from

VBAT 3.6 V dc Battery Voltage

(High Gain)

(Enable)

Typical Value Frequency Prod Probe

Comments

UEM

UPP.

0.2 V = Max Gain

1.8 V = Min Gain

UEM

(Nominal Voltage 3.6 V dc)

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

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

* 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 8 and Figure 9.

2118 (RH-77) RF Description and Troubleshooting Nokia Customer Care

Figure 8 shows each test point for the N601 TXIC section from Table 1, “Cell Transmitter

Test Points,” on page 8. Always attach a 20 dB 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 N601 TXIC section.

(Bottom right) A zoomed view of the N601 TXIC section with part numbers.

2118 (RH-77)

Nokia Customer Care RF Description and Troubleshooting

Figure 9 shows each testing point for the PA section from Table 1, “Cell Transmitter Test

Points,” on page 8. Always attach a 20 dB 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.

Table 2: Tx AGC Tuning Steps

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

2118 (RH-77) RF Description and Troubleshooting Nokia Customer Care

Table 2: Tx AGC Tuning Steps (Continued)

*Not an actual FlaLi tuning PDM. The PDM produces approximately 25 dBm at the antenna

connector.

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.

Tx Tuning AGC Step

Tx AGC (6) -94 15 6 24

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

Tx AGC PDM Value

Table 3: PA Power and Gain Measurements

Power Amp Input Test Point

pin3-Z601 left-R814

Table 4: PA Power and Gain Specifications

Target Power

Low Limit

Power Amp Output Test Point

High Limit

Mode Name

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

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

Power Output Range

Nominal Gain Vcc Range Vcc Test Point

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

Cell PMIC

The following tables show the PMIC troubleshooting information.

Table 5: PMIC Setup

Mode Tx Rx Band

Local On On CELL

2118 (RH-77)

Nokia Customer Care RF Description and Troubleshooting

Table 6: PMIC Measurements

Pin Label Test Point Units Depends On Comments

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

4NC NC NC NC NC

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

inductor.

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 pin 12,

9 VSS GND GND GND Digital GND, shared gnd with pin 13

10 NC NC NC NC NC

11 Vbgap NC NC NC Bandgap voltage output

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

0.75 - 4 M0, M1 PMIC bypass output used at Pout > 12 dBm

14, and 15

and pin 13

Table 7: Good Mobile Terminal PMIC Resistances

Pin Resistance

1 60 k

2 75 k

3 80 k

4 1.59 M

51.6 M

62 M

72 M

82 M

90.1

10 100

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