Nokia NSW-5 Series Service Manual page 245

PAMS Technical Documentation
AMPS, PL2, CH383
Y
Check current
consumption
I: >700 mA
N
Y
Press down PA
Inreasing current
consumption ?
N
Check gain control
Y
voltage at C720
V: >2.2 V
N
Check TXC N
V: >1.5 V
Y
Start Power control
troubleshooting
Check Cobba
TXCDAC
(BaseBand)
Issue 1 10/00
Disassembly and Troubleshooting Instructions
Note!
Check Antenna Circuit
and Duplex–filter.
Short–circuits in PA?
Change PA
Check possibility for
delamination
Y
Check PA input PWR
P: > 0 dBm
N
Y
Check Z901 filter
insertion loss
<4dB
N
Y
TX driver input power
P: > –20 dBm
N
E Nokia Mobile Phones Ltd.
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.
Change PA
Check R903 and
C913
Change driver N902
NSW-5
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