Troubleshooting Diagrams For Tx; Amps Tx - Nokia NSW-6 Series Disassembly & Troubleshooting Instructions

PAMS Technical Documentation

Troubleshooting diagrams for TX

AMPS TX

Connect an RF–cable to the antenna interface and connect the cable to a
spectrum analyzer input. Start WinTesla–software and set the phone to
Analog mode. Set channel 383 and Powerlevel 2 and measure RF ouput
level. Please notice insertion loss of the cable and attenuations in the test
jig or antenna adapter. It is recommended to use an external attenuator to
avoid overloading the spectrum analyzer.
AMPS, PL2, CH383
Check current
consumption
I: >700 mA
N
Press down PA
Inreasing current
consumption ?
N
Check gain control
voltage at C720
V: >2.5 V
N
Check TXC
V: >1.5 V
Y
Start Power control
troubleshooting
Check COBBA
TXCDAC
(BaseBand)
Issue 1 12/99
Y
Check Antenna Circuit
and Duplex–filter.
Chort circuit in PA?
Y
Change PA
Check possibility for
delamination
Check PA input PWR
Y
P: > 0 dBm
N
Check Z901 filter
N
insertion loss
<4dB
N
TX driver input power
P: > –20 dBm
N
N
E Nokia Mobile Phones Ltd.
Disassembly & Troubleshooting
Note!
In AMPS mode PA pin 16 bias–
Voltage should be > 2.2V.
Check all supply voltages and solderings
Check also N900 pin3 frequency and
input power. Should be > –8 dBm and
f = 997.68 MHz. If not start synth trouble
shooting (TX–LO is missing)
Delamination means, that the
chip has loosened inside the
package during reflow.
Y Change PA
Check C909, R905 and
Y
C910
Y
Change driver N902
NSW-6
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