Transmitter Fault (3) - Nokia NSE–3 SERIES Service Manual

NSE–3
Disassembly & Troubleshooting Instructions

Transmitter Fault (3)

Power
Control
TXLEV5
Transmitter working OK
YES
N250 pin 11,
TXC – pulse OK
YES
N620 pin 11 and 12 pulses
are about the same
TXC – pulse:
Oscilloscope picture in Appendix D
Page 30
NO
Transmitter
Fault
NO
Check TXC – line from N250
pin 17, if OK change N250
NO
V550 anode,
DC–voltage ~0.8V
YES
N620 pin 12,
loading ~4 k Ω
YES
Check C554, R553 and
R554, if OK change V550
Technical Documentation
NO
Check VSYN_1 voltage
through R550, R551 and R552
NO
Check C632, if OK
change N620
Original, 11/97
PAMS