Tone Send Test - Oki OKIFAX4550 Maintenance Manual

7.12

Tone Send Test

Start
Perform TONE SEND TEST.
(See 6.9.)
Connect leads of frequency
counter (or oscilloscope)
across the line terminals
L1 and L2.
Tones appear at
L1 and L2?
Yes
End
41309401TH Rev.4
Note 1:
No
Tones appear across Pin A4 (S)
and Pin B1 (0V) of CN10 (MCNT)?
Yes
Replace NCU Board.
Solved?
No
Replace MCNT Board.
The tonal frequency (2100 Hz) will be sequentially
sent for 5 seconds on the line terminals L1 and L2.
No
Replace MCNT board.
Signal route:
<46F>
IC8-87 to 95 (D0 to D7)→
IC8-28, 29 → IC12-7 (S)→
CN10-A4 (S)
<R46>
IC6-87 to 95 (D0 to D7)→
IC6-28, 29 → IC10-7 (S)→
CN10-A4 (S)
Yes
Possible cause:
CML signal
Return to section 7.1
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