Nokia 6610 - Troubleshooting diagram for GSM900 receiver

NHL-4/4U Company confidential
Troubleshooting Instructions CCS Technical Documentation
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No
No
Yes
Yes
NoNo
Yes
No
Yes
NoYes
Yes
Yes
Apply –90dBm
942.46771MHz signal
from generator to anten-
na connector
Oscilloscope at RX_I
Signal 700mVpp
DC offset 1.35V***
Frequency 67.7kHz
No
Change ge-
nerator level
to –50dBm
Spectrumanalyzer
Antenna Switch
outputs, GSM900
–88 dBm
Spectrumanalyzer
Antenna Switch
input
–84 dBm
Oscilloscope
VR1,3...6 2.7V
Check HELGA serial
interface
(burst mode)
Synthesiszer trou-
bleshooting
Spectrumanalyzer
4G VCO out
3769.6MHz
∼–30 dBm (*
Oscilloscope
VANT_1...3 0V
Oscilloscope :
Check HELGA
serial interface
(burst mode)
Check HELGA
N500
Check Base-
band
* Spectrumanalyzer
reading with 1 kohm
passive probe (right val-
ue add +34 dB)
All spectrumanalyzer reading
values are measured with
2.5 kohm passive probe (use
tweezers to connect the
probe ground to the nearest
PWB ground). Reading value
is represented without
+34 dB compensation.
900RX chain
functional
Check C831,
L811
Check Antenna
switch
Z800
Spectrumanalyzer
HELGA inputs
GSM900
–89 dBm
Check L809
L810
Check Base-
band
No
Yes
Yes
Check HELGA
N500
* ** DC–level of RXI/RXQ in
continuous mode will decrease
slowly.
The original level can be resto-
red by rewriting gain set.