Nokia 7250, 7250i Manuales De Servicio
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No
No
Yes
Yes
No
No
Yes
No
Yes
No
Yes
Yes
Yes
Apply –90dBm
942.46771MHz signal
from generator to anten-
na connector
942.46771MHz signal
from generator to anten-
na connector
Oscilloscope at RX_I
Signal 700mVpp
DC offset 1.35V***
Frequency 67.7kHz
Signal 700mVpp
DC offset 1.35V***
Frequency 67.7kHz
No
Change ge-
nerator level
to –50dBm
nerator level
to –50dBm
Spectrumanalyzer
Antenna Switch
outputs, GSM900
–88 dBm
Antenna Switch
outputs, GSM900
–88 dBm
Spectrumanalyzer
Antenna Switch
input
–84 dBm
Antenna Switch
input
–84 dBm
Oscilloscope
VR1,3...6 2.7V
Check HELGA serial
interface
(burst mode)
VR1,3...6 2.7V
Check HELGA serial
interface
(burst mode)
Synthesiszer trou-
bleshooting
bleshooting
Spectrumanalyzer
4G VCO out
3769.6MHz
4G VCO out
3769.6MHz
∼
–30 dBm (*
Oscilloscope
VANT_1...3 0V
VANT_1...3 0V
Oscilloscope :
Check HELGA
serial interface
(burst mode)
Check HELGA
serial interface
(burst mode)
Check HELGA
N500
N500
Check Base-
band
band
* Spectrumanalyzer
reading with 1 kohm
passive probe (right val-
ue add +34 dB)
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.
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
functional
Check C831,
L811
Check Antenna
switch
Z800
switch
Z800
Spectrumanalyzer
HELGA inputs
GSM900
–89 dBm
HELGA inputs
GSM900
–89 dBm
Check L809
L810
L810
Check Base-
band
band
No
Yes
Yes
Check HELGA
N500
N500
* ** DC–level of RXI/RXQ in
continuous mode will decrease
slowly.
The original level can be resto-
red by rewriting gain set.
continuous mode will decrease
slowly.
The original level can be resto-
red by rewriting gain set.