User Guide

PAMS
Technical Documentation
NSE–6
Disassembly & Troubleshooting Instructions
Page 28
Original 08/98
Transmitter Fault (1)
Transmitter
Fault
TXLEV 5
N540 pin 8
232 MHz SL: –28 dBm
N540 pin 44 and 45,
116 MHz SL: –40 dBm
VHFLO
N620: TXQP, TXQN, TXIP
and TXIN, OK ?
Check TXQP, TXIP, TXQN, TXIN
lines from COBBA, R746, R745,
soldered joints at N540 and and N250,
if OK change N250
N540 pin 47, VTX–pulse
OK ?
Check VTX supply voltage
from CCONT
N540 pin 41,
Check VREF_1 – line
N540 pin 42,
loading 15 k
Ω
Check R543 and soldered
joints
N540 pin 44 and 45,
Change N540
N500 pin 2 and 3
116 MHz SL: –6 dBm
N500 pin 2 and 3,
loading > 1M
Ω
Check N500 pin 2 and
3 for short circuits, if
OK change N500
Check C760, C761, L760, L761,
R760, R761, if OK
change N500
N500 pin 13 (RX–Continous),
SL: –28 dBm
UHFLO
N500 pin 30,
SL: 2.5 dBm
N500 pin 1 and 29,
~2.8V
Check VTX supply voltage
from CCONT
N500 pin 16,
~1.5V
Check VREF_2 – line(J518)
N500 pin 20,
loading 8k2
Ω
Check R507 and soldered
joints
Change N500
Transmitter
1
N540 pin 32
TXP–pulse OK?
Check TXP–line from MAD
N540 pin 34, TXC–pulse OK?
Check TXC–line from COBBA
TXQP, TXIP, TXIN, TXQN, TXP and VTX: Oscilloscope pictures in Appendix C
YES
YES
YES
YES
YES
YES YES
YES
YES YES
YES
YES YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
~1.5V
~0.8V
R748, R749 and