High-Speed Modem Test (G3 Dual Line) - Oki OKIFAX 5750 Maintenance Manual

7.28 High-speed Modem Test (G3 Dual Line)

Start
Connect oscilloscope probe
across the line terminals
L1 and L2
Perform H-MODEM SEND
TEST G3 for the transmitter and
H-MODEM REC TEST G3 for
the receiver. (See Fig. 6.9.1)
Which mode, TX or RX?
TX
Modem's signal appears
across L1 and L2?
No
Modem's signal appears
across
CN3 (WN5)?
Yes
Modem's signal appears
across CN2-A8, B8 (S)
of G3A board?
Yes
Replace DM2 Board
41285901TH Rev.3
RX
A
Yes
TX End
No
Replace WN5 Board.
Solved?
No
Replace G3A Board.
No
Replace G3A Board.
Signal route:
IC202-9→ IC203-6, 7
→ IC203-2, 1→ CN2-A8, B8
Signal route:
CN3-15, 16→T1-3, 1→
CN1-3, 4
Yes
Possible cause:
CML signal
Return to section 7.23
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