Oki OKIFAX 5750 Maintenance Manual page 855

3.9.10 Receiving NG
10: 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.
Yes
During protocol signal sending,
sine wave or modulated sine
wave output is provided pin 1
of IC203.
Yes
Replace G3A board.
41285901TH Rev.3
Yes
5V and 0V are alternately
input to pin 9 of IC23,
synchronized with the
RING signal.
No
Check CN2.
Yes
During protocol signal receiving,
sine wave or modulated sine
wave input is provided pin 3
of IC204.
Yes
During protocol signal receiving,
sine wave or modulated sine
wave input is provided pin 11
of IC202.
Yes
No
Replace IC202.
No
Replace IC203.
Yes
5V and 0V are altermately
input to pin 38 of IC1,
synchronized with the
RING signal
Yes
Replace IC1.
No
Check CN2.
No
Replace IC204.
No
Replace IC23.
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