Receiving Ng - Oki OKIFAX4550 Maintenance Manual

4.1.8 Receiving NG

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 between pin
28 and pin 29 of IC8
Yes
During protocol signal sending,
sine wave or modulated sine wave
output is provided at pin 7 of IC12
Yes
Check CN10.
41309401TH Rev.4
Yes
5V and 0V are alternately
input to pin 9 of IC14,
synchronized with the
RING signal
No
Check CN10.
Yes
During protocol signal receiving,
sine wave or modulated sine wave
input is provided between pins
2 and 3 of IC12
Yes
During protocol signal receiving,
sine wave or modulated sine wave
output is provided at pin 32 of IC8
Yes
No
Replace IC8.
No
Yes
Pin 195 of IC2 repeats 5V
No
and 0V cyclically, synchronized
with the RING signal
Replace IC14.
No
Check CN10.
No
Replace IC12.
Yes
Replace IC2.
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