Nokia 2355 Service Manual
Nokia Customer Care
2355 (RM-121)
Mobile Terminal
RF Description and
Troubleshooting
ISSUE 1 02/2006 |
Company Confidential |
©2006 Nokia Corporation |
2355 (RM-121) |
|
RF Description and Troubleshooting |
Nokia Customer Care |
Contents |
Page |
Mobile Terminal Components ..................................................................................................................... |
3 |
Preliminary RF Troubleshooting.................................................................................................................. |
4 |
Mobile Terminal Cannot Make a Call .................................................................................................... |
4 |
Tx Power Low ................................................................................................................................................ |
4 |
Transmitter Block Diagram ....................................................................................................................... |
5 |
Transmitter Schematics ............................................................................................................................. |
6 |
Transmitter Troubleshooting .................................................................................................................... |
8 |
CELL Tx Setup............................................................................................................................................. |
8 |
Failed Test: Tx PA Detector .................................................................................................... |
............. 10 |
Tx RF Test Points ........................................................................................................................................ |
12 |
Tx AGC Tuning ............................................................................................................................................ |
15 |
Receiver Troubleshooting ........................................................................................................................ |
16 |
Receiver Schematics ................................................................................................................................. |
17 |
Turning on the Rx Path ......................................................................................................... |
............... 19 |
Switching the Rx Gain, IF, and IP States ............................................................................................ |
20 |
Receiver Troubleshooting ........................................................................................................................ |
21 |
Receiver RF Troubleshooting Test Points ............................................................................................ |
22 |
Receiver IF Troubleshooting Test Points ............................................................................................ |
24 |
Cell Receiver Check from RF to IQ ........................................................................................................ |
26 |
Receiver Diagnostic using Signal Tracing and Call Box.................................................... |
.......... 27 |
Rx Front-End IC (N7150) DC Troubleshooting .................................................................................. |
28 |
Synthesizer Troubleshooting .................................................................................................................. |
28 |
Synthesizer Block Diagram ...................................................................................................... |
........... 29 |
Synthesizer Schematic ............................................................................................................................. |
30 |
Synthesizer Troubleshooting Setup ...................................................................................................... |
31 |
19.2 MHZ VCTCXO Reference Clock ..................................................................................................... |
33 |
VCTCXO Manual Tuning ........................................................................................................................... |
33 |
UHF Synthesizer Test Points ................................................................................................................... |
37 |
UHF Synthesizer Schematic .................................................................................................................... |
38 |
Incorrect UHF Frequency ........................................................................................................ |
............. 39 |
Rx VHF ........................................................................................................................ |
..................................39 |
Rx VHF Schematic ..................................................................................................................................... |
40 |
Incorrect Rx VHF Frequency ..................................................................................................... |
.......... 40 |
Tx VHF ........................................................................................................................................................... |
41 |
Tx VHF Schematic ...................................................................................................................................... |
42 |
Incorrect Tx VHF Frequency ..................................................................................................... |
........... 43 |
FM Radio Troubleshooting ...................................................................................................................... |
44 |
FM Radio Troubleshooting Setup .......................................................................................................... |
44 |
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©2006 Nokia Corporation Company Confidential |
ISSUE 1 02/2006 |
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RF Description and Troubleshooting |
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Mobile Terminal Components
Figure 1 illustrates the main components of the 2355.
RF connector
Cell isolator |
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Rx IC |
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PA PMIC |
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Cell duplexer |
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Cell Rx RF |
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DC-DC |
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converter |
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SAW filter |
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Cell Tx PA |
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RF IF CDMA filter |
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Cell Tx SAW |
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VCO |
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filter |
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Rx Downconverter |
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Tx Upconverter |
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VCTCXO |
UIM card |
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UPP (BB) |
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UEM (BB) |
Figure 1: Component layout (bottom)
ISSUE 1 02/2006 |
©2006 Nokia Corporation Company Confidential |
Page 3 |
2355 (RM-121) |
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RF Description and Troubleshooting |
Nokia Customer Care |
Preliminary RF Troubleshooting
The following sections identify steps to troubleshoot some common RF issues.
Mobile Terminal Cannot Make a Call
Verify the following items 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 Batch Tune 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 "VCTCXO Manual Tuning" on page 33
7.The transmitter and receiver are working properly in Local Mode. See "Transmitter Troubleshooting" on page 8 and "Receiver Troubleshooting" on page 16 for detailed information.
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 proper placement, rotation, and soldering of components.
3.Look for the presence of a Tx signal on a spectrum analyzer at the correct 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.)
4.Ensure that the power supplies to the Tx have the correct voltage.
5.Ensure that the AGC PDMs are set for the desired Tx power and that the AGC voltages are correct.
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©2006 Nokia Corporation Company Confidential |
ISSUE 1 02/2006 |
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2355 (RM-121) |
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Nokia Customer Care |
RF Description and Troubleshooting |
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Transmitter Block Diagram
Following is the block diagram for the Tx RF system. I
TP1 |
TP4 |
TP2 TP3
Figure 2: Tx system block diagram
ISSUE 1 02/2006 |
©2006 Nokia Corporation Company Confidential |
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RF Description and Troubleshooting |
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Transmitter Schematics
The following schematics are for general reference only. See the Schematics chapter for detailed versions.
Figure 3: Transmitter schematic 1
ISSUE 1 02/2006 |
©2006 Nokia Corporation Company Confidential |
Page 6 |
2355 (RM-121) |
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RF Description and Troubleshooting |
Nokia Customer Care |
Figure 4: Transmitter schematic 2
Page 7 |
©2006 Nokia Corporation |
Company Confidential |
ISSUE 1 02/2006 |
2355 (RM-121) |
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RF Description and Troubleshooting |
Nokia Customer Care |
Transmitter Troubleshooting
CELL Tx Setup
Use the following procedures to prepare for CELL Tx troubleshooting using Phoenix.
1.Connect RF test connector to a call box.
2.Connect the phone to a PC using the dummy battery adapter, and connect a power supply.
3.Open the Troubleshooting menu, and click Phone Control. The Phone Control dialog box appears.
4.On the Phone Control dialog box, click the LOCAL button in the Phone State area to put the phone into Local Mode.
Figure 5: Phone Control dialog box
5.Open the Troubleshooting menu, point to RF, and click CDMA Control. The RF Main Mode dialog box appears.
6.Select the following values on the RF Main Mode dialog box:
•Band = Cell (CDMA)
•Channel = 384
•Mode = Rx/Tx
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ISSUE 1 02/2006 |
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Nokia Customer Care |
RF Description and Troubleshooting |
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Figure 6: RF Main Mode dialog box
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. The CDMA Control dialog box appears.
Figure 7: CDMA Control dialog box for Cell Tx troubleshooting
9.Select the following values on the CDMA Control dialog box.
•State = Rho ON
•Band = Cell
•Radio Configuration = Mode 1: IS-95 Voice
•Select the Set default PDM values check box.
10.Click Execute.
11.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.
12.Open the Troubleshooting menu, point to RF, and click PDM Control.
The RF PDM Control dialog box appears.
ISSUE 1 02/2006 |
©2006 Nokia Corporation Company Confidential |
Page 9 |
2355 (RM-121) |
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RF Description and Troubleshooting |
Nokia Customer Care |
Figure 8: RF PDM Control dialog box for Cell troubleshooting
13.Click Read Phone to update the values.
14.Configure the spectrum analyzer using the following values:
•Center Frequency = 836.52 MHz
•Span = 100 MHz
•RF LVL Amplitude = 20 dBm
•Attenuation = Auto
•BW = Auto
Adjust the following PDM field values on the RF PDM dialog box:
•Set PA Gain State to High
•Adjust Tx RF AGC PDM to around –250
•Adjust Tx IF AGC PDM to around –250
•Set Output level to +23dBm on CH-384 and monitor the current between 590mA and 660mA.
Failed Test: Tx PA Detector
1.Use Phoenix to set the phone in Local Mode, and activate the Tx with default output power. The output power at the RF test connector should read
9 dBm +/- 4 dB.
2.Use a voltmeter on DC, and probe the detector output at C813. The voltmeter should read approximately 1.4 V. If not, replace the detector (N803).
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©2006 Nokia Corporation Company Confidential |
ISSUE 1 02/2006 |
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RF Description and Troubleshooting |
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Good output |
Bad output |
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Figure 9: The output of the mobile terminal on a spectrum analyzer should look like the figure on the left
If using the AAS-10 probe with the phone connected to the call box, the amplitude should be approximately -7 dBm at the antenna test point on the top of the PWB.
ISSUE 1 02/2006 |
©2006 Nokia Corporation Company Confidential |
Page 11 |
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RF Description and Troubleshooting |
Nokia Customer Care |
Tx RF Test Points
Figure 10 and Figure 11 are the transmitter DC/RF test points. See Table 1 on page 14 for test point descriptions and values.
1 |
2 |
3 |
4 |
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TP12
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PNMIC |
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9 |
DC-DC |
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TP11 |
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TP3 |
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TP13
TP4
Figure 10: Tx DC/RF test points - PA section
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©2006 Nokia Corporation Company Confidential |
ISSUE 1 02/2006 |
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2355 (RM-121) |
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Nokia Customer Care |
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RF Description and Troubleshooting |
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Following are the Tx DC/RF test points for the N7000 Tx Section |
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TP5 TP9
TP91 |
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N7000 Tx |
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TP6 |
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TP2 |
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TP10 |
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Tx SAW |
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TP3 |
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TP8
TP7
Figure 11: Tx DC/RF test points - N7000 section
ISSUE 1 02/2006 |
©2006 Nokia Corporation Company Confidential |
Page 13 |
2355 (RM-121) |
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RF Description and Troubleshooting |
Nokia Customer Care |
Table 1 shows the Tx DC/RF test points to probe (see Figure 10 and Figure 11) when troubleshooting the cell transmitter path. It is recommended that you follow the steps in order.
Table 1: Tx DC test points
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Typical Value/ |
Typical Value/ |
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Test Point |
FUnction |
Frequency |
Frequency |
Comments |
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HP85024A |
Prod Probe |
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TP1 Z7000 |
N7000 - Out |
-40 dBm/ 1MHz |
-13.2dBm/ |
Output of N7000 Driver, |
pin 1 |
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836.52MHz |
836.52MHz |
Input to Tx SAW Filter |
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TP2 Z7000 |
PA - In |
-26 dBm/ 1MHz |
-15.4 dBm/ |
Output of Tx SAW, |
pin 3 |
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836.52MHz |
836.52MHz |
Input to PA |
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TP3 Z7400 |
PA - Out |
5.0 dBm/ 1MHz |
18.3 dBm/ |
Input to Isolator |
In |
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836.52MHz |
836.52MHz |
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TP4 Z7400 |
Iso - Out |
2.5 dBm/ 1MHz |
10.3 dBm/ |
Output of Isolator, |
Out |
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836.52MHz |
836.52MHz |
Input to Duplexer |
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TP5 C7002 |
IF - Out |
-29 dBm/ 1MHz |
-24 dBm/ |
Tx IF probing point at IF |
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228.6MHz |
228.6MHz |
filter |
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TP6 |
VR5 |
2.75V dc |
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VHF VCO/PLL, IQ modulator |
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supply from UEM |
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TP7 |
VR7 |
2.75V dc |
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UHF PLL supply from UEM |
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TP8 |
VR2 |
2.75V dc |
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Mixer, driver, and IF supply |
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from UEM |
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TP9 R7002 |
VAGC-RF |
0.2 to 1.8V dc |
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Tx AGC control voltage |
TP91 R7001 |
VAGC-IF |
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from UPP. |
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0.2V = Max Gain |
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1.8V = Min Gain |
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TP10 |
VIO-Tx |
1.8V |
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Supply for digital circuits |
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from UEM |
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TP11 |
VBAT |
3.2V dc |
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Battery voltage (nominal |
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voltage 3.7V dc) |
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TP12 |
VCC |
3.1V dc (High Gain) |
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Main PA supply voltage |
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from PMIC. |
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Lgain=0.8V, Mgain=1.25V, |
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Hgain=Vbat |
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TP13 C7407 |
VG/Vref |
4.6V dc (Enable) |
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PA gate voltage (Enable/ |
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Disable). Disable=0V |
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Page 14 |
©2006 Nokia Corporation Company Confidential |
ISSUE 1 02/2006 |
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