High-Speed Modem Test - Oki OF5900 Maintenance Manual

7.13

High-speed Modem Test

Start
Connect oscilloscope probe
across the line terminals
L1 and L2
Perform H-MODEM SEND
TEST for the transmitter and
H-MODEM REC TEST 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 CN11-A25 (S)
of MCNT (R76) board?
Yes
Replace C34 or H34 Board
Signal route:
IC202-9 IC203-6, 7
IC203-2, 1
OKIFAX 5700/5900
RX
Yes
No
Replace WN5 Board.
Solved?
Replace MCNT(R76) Board.
No
Replace MCNT(R76) Board.
Signal route:
CN12-A8, B8
CN201-2
A
TX End
Signal route:
CN3-15, 16 T1-3, 1
CN1-3, 4
Yes
No
Possible cause:
CML signal
CN11-A25
7 - 16
Return to section 7.1