Oki OKIFAX 5750 Maintenance Manual page 789

3.1.8 Receiving NG (include C34/H34)
8: Receiving NG.
RING signal cannot be
detected
No
Protocol signal receiving is NG.
No
Signals cannot be sent.
During protocol signal sending,
sine wave or modulated sine
wave output is provided pin 9
of IC202 (on C34/H34 board).
Yes
During protocol signal sending,
sine wave or modulated sine
wave output is provided pin 1
of IC203 (on C34/H34 board).
Yes
Check CN11 or CN12,
CN201 (on C34/H34 board).
41285901TH Rev.3
Yes
5V and 0V are alternately
input to pin 9 of IC23,
synchronized with the
RING signal.
No
Check CN12.
Yes
During protocol signal receiving,
sine wave or modulated sine
wave input is provided pin 3
of IC204 (on C34/H34 board).
Yes
During protocol signal receiving,
sine wave or modulated sine
wave input is provided pin 11
of IC202 (on C34/H34 board).
Yes
No
Replace IC202
(on C34/H34 board).
No
Replace IC203
(on C34/H34 board).
Yes
5V and 0V are altermately
input to pin 63 of IC2,
synchronized with the
RING signal
Yes
Replace IC2.
No
Check CN11 or CN12,
CN201 (on C34/H34 board)
No
Replace IC204
(on C34/H34 board).
No
Replace IC23.
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