Nokia RH-37 Series Rf Troubleshooting Instructions page 17

Nokia Customer Care
If selected band = GSM1900
Spectrum Analyzer:
Check SAW filter Z7801:
TP: OUT-Z7801
Output signal > Pref - 3.5dB
No
Spectrum Analyzer:
Check external LNA V7800:
TP: OUT-V7800
Output signal > Pref +14dB
Spectrum Analyzer:
Check balun T7800 and matching network:
TPs: INM_P_RX / INP_P_RX
Both output signals > Pref +12dB
RF ASIC N7500 seems to be
defective. Exchange N7500.
Issue 1 07/04
Yes
1)
Yes
1)
No
Yes
1)
Yes
Nokia Corporation
6(b) - RF Troubleshooting Instructions
No
Yes
No
Oscilloscope:
Check voltages for V7800:
Voltage at C7802 = 2.5V ?
Voltage at C7800 = 0V ?
Yes
No
1)
Note :
RF levels are dependent on RF probe and have to be validated
with a known good sample.
RH-37
Receiver
Fault Finding Tree
part 9
Change Z7801
Check supply
filter components
No
around V7800
and RF ASIC
Change T7800
Page 17