Nokia 6610 Troubleshooting Instructions page 20

NHL-4/4U
Troubleshooting Instructions
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Apply –90dBm
1842.86771MHz signal
from generator to anten-
na connector
Yes No
Oscilloscope at
RX_I /RXQ
Signal 160mVpp
DC offset 1.35V ***
Frequency 67.7kHz
Yes
GSM1800 RX chain
functional
Spectrumanalyzer
HELGA inputs
GSM1900
–78 dBm
Oscilloscope
VR1,3...6 2.7V
Check HELGA serial
interface
(burst mode)
Spectrumanalyzer
4G VCO out
3685.6MHz
∼–30 dBm (*
Check HELGA
N500
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Yes
Change ge- Spectrumanalyzer
Antenna Switch out-
nerator level
put, GSM1900
to –50dBm
–88 dBm
Spectrumanalyzer
RX_SAW_out
Yes
–90 dBm
Oscilloscope
LNA_VCC 2.6V
LNA_P 0 V
Yes
Check V802,
C826, Z802,
C829, C8097,
C808
Check Baseband
Yes
Synthesiszer trou-
bleshooting
Yes
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CCS Technical Documentation
No No
Spectrumanalyzer
Antenna Switch input
–84 dBm
Yes
No
Oscilloscope Oscilloscope
VANT_3 2.7VV
Check HELGA se-
VANT_1/2 0V
rial interface (burst
mode)
Yes
Check Antenna
switch Z800
Check HELGA
N500
Check Baseband
Oscilloscope
VR1,3...6 2.7V
Check HELGA serial
interface
(burst mode)
Yes
Check HELGA
N500
Check C831,
L811
No
Check Base-
band
Yes
Check Baseband
All spectrumanalyzer reading
values are measured with 1
kohm passive probe (use
tweezers to connect the
probe ground to the nearest
PWB ground). Reading value
is represented without +26
dB compensation.
* Spectrumanalyzer
reading with 1 kohm
passive probe (right val-
ue add +26 dB)
* ** DC–level of RXI/RXQ in
continuous mode will decrease
slowly.
The original level can be resto-
red by rewriting gain set.
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