Nokia 3220 Service Manual 06(b) rh37 rf trouble
Nokia Customer Care
RH-37 Series Transceivers
6(b) - RF Troubleshooting
Instructions
Issue 1 07/04 2004 Nokia Corporation Page 1
Company Confidential
RH-37
6(b) - RF Troubleshooting Instructions Nokia Customer Care
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Nokia Customer Care 6(b) - RF Troubleshooting Instructions
Table of Contents
Page No
General Information on RF Troubleshooting.................................................................................... 5
Test environment ..................................................................................................................................5
Test conditions ......................................................................................................................................6
Receiver Verification and Troubleshooting ...................................................................................... 7
General instructions for RX troubleshooting ................................................................................7
Measuring RX I/Q signals using RSSI reading ..............................................................................7
Measuring RX performance using SNR measurement ............................................................ 9
Measuring front-end power levels using spectrum analyzer............................................. 10
Measuring analogue RX I/Q signals using oscilloscope....................................................... 11
Fault finding chart of the receiver ................................................................................................12
Transmitter ............................................................................................................................................. 19
General instructions for TX troubleshooting ..............................................................................19
GSM900 transmitter ..........................................................................................................................19
General instructions for GSM TX troubleshooting ................................................................ 19
Fault finding chart for GSM900 transmitter .......................................................................... 22
GSM1800 transmitter .......................................................................................................................24
General instructions for GSM1800 TX troubleshooting ...................................................... 24
Fault finding chart for GSM1800 transmitter........................................................................ 26
GSM1900 transmitter .......................................................................................................................28
General instructions for GSM1900 TX troubleshooting ...................................................... 28
Fault finding chart for GSM1900 transmitter........................................................................ 30
Synthesizer ............................................................................................................................................. 33
General instructions for synthesizer troubleshooting ..............................................................33
Checking synthesizer operation .....................................................................................................33
Fault finding chart for PLL synthesizer ........................................................................................36
Frequency tables .................................................................................................................................38
GSM900 (including EGSM900)................................................................................................... 38
GSM1800 .......................................................................................................................................... 39
GSM1900 .......................................................................................................................................... 41
DC Supply Voltage Check ................................................................................................................... 43
Appendix 6A: Test Points..................................................................................................... 45
Receiver test points ...........................................................................................................................47
Transmitter test points ......................................................................................................................49
Synthesizer test points ......................................................................................................................52
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6(b) - RF Troubleshooting Instructions Nokia Customer Care
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Nokia Customer Care 6(b) - RF Troubleshooting Instructions
General Information on RF Troubleshooting
Notes:
Several bills of material (BOM): There are two different kinds of VCOs, VCTXOs, RF-PAs, SAW-filters and Antenna Switches (ASM) assembled. They may only be replaced with the same type as the
original component (from the same manufacturer).
Phoenix version: In this document there are example measurements being depicted with pictures of
AMS-Phoenix, version A 2004.06.1.69. In later versions pictures of menus and windows may look differently.
Layout version: The drawings of test points and component placement in this version of the document
are taken from build B4.0 layout (1cna_41). If you use the document for newer layout versions, make
sure to use the corresponding assembly and test point drawings.
Test environment
It is assumed, that the phones are disassembled and tested with a repair jig MJ-22R.
The following measurements have to be done for repairing the phone boards:
• RF measurements shall be done using a spectrum analyzer together with a highfrequency probe. Note that the signal will be significantly attenuated. Correct
attenuation can be checked using a “good” phone board for example.
• LF (low frequency) and DC measurements shall be carried out with an oscillo-
scope together with a 10:1 probe.
•For receiver measurements, a signal generator specified for frequencies up to
2000 MHz is required. The signal generator is connected to the antenna port of
the repair jig.
Most of the radio communication testers, like CMU200, can be used as a signal
generator, but make sure to have a continuous (CW) signal without modulation
for alignment purposes.
• Transmitter output level measurements shall be done with a power meter
which is connected to the antenna port of the repair jig.
Always make sure that the measurement set-up is calibrated when measuring RF parameters at the antenna port. Remember to put the correct losses of the module repair jig
and the connecting cable in Phoenix or in the set-up programs of the RF generators
when realigning the phone.
Apart from key-components described in this document, there are a lot of discrete components (resistors, inductors and capacitors) for which troubleshooting has to be done by
checking its proper soldering and complete assembly on the PWB. Capacitors and resistors can be checked by means of an ohm-meter, but be aware in-circuit measurements
should be evaluated carefully.
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Test conditions
Rx tuning of the 26 MHz reference oscillator (VCTCXO) is temperature sensitive
because of the estimations of <AFC_value> and <AFC_slope>. According to the Production Test Specification DCS02294-EN-0.5, the ambient temperature has to be within a
temperature range of 22°C to 28°C.
Most RF semiconductors are static discharge sensitive. ESD protection must be taken
into account during repair (ground straps and ESD soldering irons).
The RF ASIC Helgo is moisture sensitive. Therefore, the ASIC must be pre-baked prior
to soldering.
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Nokia Customer Care 6(b) - RF Troubleshooting Instructions
Receiver Verification and Troubleshooting
General instructions for RX troubleshooting
Connect the phone to a PC, which has Phoenix Service Software and a dongle installed,
using either
• repair jig and DAU-9S (RS232) cable or
• repair jig and XCS-4 cable via FPS-8 Flash Box or
• DAU-9T cable (RS232).
Connect the phone to a power supply (DC voltage: 3.6V, max. current: 3A) and an RF signal generator. Switch the phone on.
Start Phoenix Service Software and open FBUS connection.
Select Scan Product Ctrl-R
and wait until the phone information (RH-37) is shown in the lower right corner of the
screen.
Follow the instructions below.
Measuring RX I/Q signals using RSSI reading
Start Phoenix Service Software and open FBUS connection.
Select Scan Product Ctrl-R
Wait until the phone information is shown in the lower right corner of the screen.
Set the operating mode to local mode
Select Testing T
RF Controls F
Select Band GSM 900 or GSM1800 or GSM1900
Active unit RX
Operation mode Burst
RX/TX Channel 37 or 700 or 661
Select Testing T
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RSSI reading R
In the RSSI Reading window, the <measuring mode> shall be set on Sum vector and the
<reading mode> on Continuous.
The set up should now look like this:
(The example below shows a screen shot in GSM900!)
Make the following settings on your signal generator:
Frequencies:
• GSM 900: 942.46771 MHz (channel 37+ 67.710 kHz offset)
• GSM 1800: 842.86771 MHz (channel 700 + 67.710 kHz offset)
• GSM 1900: 1960.06771 MHz (channel 661+ 67.710 kHz offset)
RF power level:
• – 80 dBm @ the antenna connector of the phone/ test jig
(remembering to compensate for the cable and jig attenuation).
Click on <Read now> in RSSI reading.
The resulting RSSI level shall be – 80 dBm +/– 0.5 dB in each band.
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Measuring RX performance using SNR measurement
Start Phoenix Service Software and open FBUS connection.
Select Scan Product Ctrl-R
Wait until the phone information is shown in the lower right corner of the screen.
Set operating mode to <local mode>.
Select Testing T
RF Controls F
Select Band GSM 900 or GSM1800 or GSM1900
Active unit RX
Operation mode Burst
RX/TX Channel 37 or 700 or 661
Select Testing T
SNR Measurement M
Select Measuring mode Fast SNR (Radio Button)
Press Start
The window <Signal Measurement> pops up informing on frequency and power level of
the signal generator to be set. Follow the command <Turn ON the RF generator>.
Press <ok> and the window will close.
Read the SNR result from the window SNR Measurement. The value shall exceed:
• GSM 900: > 20 dB
• GSM 1800: > 18 dB
• GSM 1900: > 18 dB
The set up should now look like this:
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(The example below shows a screen shot in GSM900!)
Choose the remaining GSM bands and measure accordingly the procedure described
above.
Measuring front-end power levels using spectrum analyzer
Spectrum analyzer (SA) level values depend on the probe type and shall be verified by a
properly working phone sample. The levels that are given in this document are measured
with a resistive probe (50 Ohm semi-rigid cable).
Start Phoenix Service Software and open FBUS connection.
Select Scan Product Ctrl-R
Wait until the phone information is shown in the lower right corner of the screen.
Set <operating mode> to <local mode>.
Select Testing T
RF Controls F
Select Band GSM 900 or GSM1800 or GSM1900
Active unit RX
Operation mode Continuous
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RX/TX Channel 37 or 700 or 661
Please refer to the fault finding chart and Appendix for proper levels at different test
points.
Measuring analogue RX I/Q signals using oscilloscope
Measuring with an oscilloscope RX I and RX Q signals on the test points <RXI> respectively <RXQ> is recommended only if the RSSI reading does not provide enough information. Input level = -60dBm.
Start Phoenix Service Software and open FBUS connection.
Select Scan Product Ctrl-R
Wait until phone information is shown in the lower right corner of the screen.
Set operating mode to <local mode>.
Select Testing T
RF Controls F
Wait until the RF Controls window pops up.
Select Band GSM 900 or GSM1800 or GSM1900
Active unit RX
Operation mode continuous
RX/TX Channel 37 or 700 or 661
AGC 10
The following picture should be displayed on an oscilloscope's screen if the receiver is
working properly:
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Signal amplitude 1.40Vpp
DC offset ≈ 1.28V as the offset is floating, switch to the operating mode
<Burst> in Phoenix and read the DC offset
Frequency 67kHz
Fault finding chart of the receiver
During fault finding, the calibration procedure is used to find out, whether all bands are
affected (error in common part of the Rx chain) or only one band (error in a Rx part of
the failed band). Take care not to save calibration values to the phone memory,
which are out of limits. Find the error first and repair it.
When a defective phone has been calibrated, a possible error in RX front-end might be
masked. In that case, one can get a reasonable RSSI reading, although the front-end
shows excessive losses. If it is not sure that incorrect re-calibration has been made, following steps shall be carried out:
• Check if AGC calibration is within limits.
• Check if SNR reading is o.k.
Use an oscilloscope to check levels of “RXI” and “RXQ”.
The RF ASIC generates only single ended I and Q signals (RXI, RXQ). As the A/D converter
in UEM requires two differential signals, an artificial mid voltage is generated from
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VrefRF02. The phone layout has dedicated test points for the analogue RX I and Q signals
(J512, J513).
The BB part is used to measure those signals by means of RSSI reading. This works only if
correct calibration has been carried out in production.
RSSIreading [dBm] = 20log(UBB/U
LSB
) - AGC
calibrated
In order to check the levels and frequencies of RF signals, the following probe can be
used (note that only the core lead contacts the test point, the shielding of the coaxial
cable does not contact GND during the measurement):
Connect this probe via a coaxial cable and a DC block to a spectrum analyzer. The DC
block is important to protect the spectrum analyzer from DC levels, which superpose
the RF signal at several test points.
If both RX and TX path seem to be faulty, it has to be checked if the synthesizer is working.
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Phoenix:
Phone: local mode
Open
Signal Generator:
Phoenix:
Open
Check RSSI Level = -80dBm
Execute Rx Calibration in selected
band, refer to chapter 9.2.1
re calibration results within limits?
Make sure that
Synthesizer is working
Yes
All 3 bands
RF Controls
Active Unit: Rx
Op. Mode: Burst
Rx/Tx channel: default (mid)
Level: –80dBm
Frequency: calculated from
Phoenix + 67.71kHz
RSSI reading
No
:
see
No
Yes next bandNo
Synthesizer Fault
Finding Tree
Yes
Selected band is working and
calibrated.
re all 3 bands measured?
Yes
Rx chain is functional
and calibrated
Receiver
Fault Finding Tree
part 1
= To be done in all
three bands.
No
re all 3 bands measured?
Yes
Are all 3 bands defective?
Yes
Oscilloscope:
Check supply voltages of RF ASIC:
VR4 = 2.8V ? (TP: VR4)
Yes
Oscilloscope:
Check supply voltages of RF ASIC:
VR6 = 2.8V ? (TP:VR6)
Yes
No
No
Continue with single
band fault finding.
No
No
Check supply filter
components (C2233,
C7519, C7520) and UEM
Check supply filter
components (C2231,
C7521) and UEM
Receiver
Fault Finding Tree
part 2
Receiver
Fault Finding Tree
part 3
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Oscilloscope:
Check reference voltages of RF part:
VrefRF01 = 1.35V ?
(TP: VrefRF01*)
Yes
No
Check supply filter
components (R7511,
C7524) and UEM
Receiver
Fault Finding Tree
part 4
Oscilloscope:
Check reference voltages of RF part:
VrefRF02 = 1.35V ?
(TPs: VrefRF02* and VrefRF02**)
Yes
Phoenix:
Phone: local mode
RF Controls
Active Unit: Rx
Op. Mode:
Rx/Tx channel: default (mid)
AGC: 14
:
Continuous
Signal Generator:
To be tuned that input power at spectrum
analyzer: –60dBm
(power at probe:
Frequency: calculated from Phoenix
offset: 67.71kHz
= approx. -63 dBm)
Pref
Spectrum Analyzer: 1)
Check Rx/Tx Switch (Diplexer)
Depending on selected band, check level at TPs:
GSM900 output Rx1 Pref -1.5dB ?
GSM1800 output Rx2 Pref -2.0dB ?
GSM1900 output Rx3 Pref -2.5dB
Yes
Check supply filter
No
components (R2900,
R2901, C2900, C2901)
and UEM
Receive
Fault Finding Tree
part 5
No
?
Change Z7800
Note 1):
RF levels are dependent on RF probe and have to be validated
with a known good sample.
Oscilloscope:
RX IQ levels ok (TPs: RXI, RXQ) ?
Yes
Oscilloscope:
RF-BB serial interface ok?
(TPs: RFBusData, RFBusClk, RFBusEna1)
No
No
Yes
Change RF
ASIC (Helgo)
BB error:
Check UPP
Change RF
ASIC (Helgo)
Receiver
Fault Finding Tree
part 6
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Select faulty band in Phoenix and continue measurements on dedicated Rx part.
Phoenix:
SNR Measurement
open
Meas. Mode: Fast SNR
Measure
Press
Signal Generator:
Level: –92dBm
Frequency: calculated from Phoenix
Phoenix:
SNR measurement ok?
(SNR > 18.37dB)?
Phoenix:
Phone: local mode
RF Controls
Active Unit: Rx
Op. Mode:
Rx/Tx channel: default (mid)
AGC: 14
.
No
:
Continuous
Single band fault finding
Yes
Front end is ok.
Phoenix:
Phone: local mode
RF Controls
Active Unit: Rx
Op. Mode:
Rx/Tx channel: default (mid)
AGC: 10
Signal Generator:
Level: –60dBm
Frequency: calculated from Phoenix
offset: 67.71kHz
Continue with Rx Fault Finding part 6.
:
Continuous
Receiver
Fault Finding Tree
part 7
Receiver
Fault Finding Tree
part 8
Signal Generator:
To be tuned that input power at spectrum
analyser: –60dBm
power at probe:
Frequency: calculated from Phoenix
offset: 67.71kHz
=approx. -63dBm)
Pref
Spectrum Analyzer: 1)
Center Freq: calculated from Phoenix
RBW 20kHz
Check Rx SAW filter and matching
network of selected band:
GSM900 TPs: INM_G_RX / INP_G_RX
both output levels > Pref -3.5dB ?
GSM1800 TPs: INM_D_RX / INP_D_RX
both output levels > Pref -6dB ?
Yes
No
Note 1):
RF levels are dependent on RF probe and have to be validated
with a known good sample.
Change Rx SAW filters (Z7802,
Z7803) or component(s) of
matching network depending on
selected band
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