No Sound From The Speaker - Oki OKIFAX4550 Maintenance Manual

4.2.10 No sound from the speaker

10: No sound from
the speaker
Monitor or buzzer
buzzer
Pulse wave input is provided
at pin 5 of IC8 when the
key is pressed or the soft
ringer goes
No
Replace CPU1.
41309401TH Rev.4
Monitor
Communication normal
No
See sending or receiving NG.
Yes
No
No
Replace IC8.
Yes
Sine wave or modulated
No
wave input is provided at
pin 13 of IC8 during
communication
Replace TR1.
Either pin 9, 10, or 11 of IC8
becomes 5V when the key is
pressed or the soft ringer goes
or during communication
Yes
Sine wave or modulated wave
is input to pin 3 of IC11 when the
key is pressed or the soft ringer
goes or during communication
Yes
Sine wave or modulated wave is
output from pin 5 of IC11 when the
key is pressed or the soft ringer
goes or during communication
Yes
Check CN9.
Yes
No
Replace IC11.
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