Tone (Tel/Fax) Send Test - Oki OF5900 Maintenance Manual

7.15

Tone (TEL/FAX) Send Test

Start
Connect oscilloscope probe
across the line terminals
L1 and L2.
Perform TONE (TEL/FAX)
SEND TEST. (See 6.12.)
Pseudo-Ring Back Tone
signal appears
across L1 and L2?
End
OKIFAX 5700/5900
No
Yes
MF signal appears across Pin 2 (S) and
Pin 1 (0V) of CN201 (C34 or H34)
MF signal appears across CN12-A8, B8
(S) and CN12-A12, B12 (0V) of
MCNT (R76) board?
Replace WN5 Board.
Yes
Replace MCNT (R76) Board.
Return to section 7.1
Note: The pseudo-ring back tone is sent to the
telephone line for TEL/FAX automatic
switching.
Yes
Replace C34 or H34
Signal route:
IC202-9 IC203-6, 7
Yes
Replace MCNT (R76) Board.
Signal route:
CN11-A25 CN12-A8, B8 (S)
Signal route:
CN3-15, 16 T1-3, 1
CN1-3, 4
Solved?
No
Possible cause:
CML signal
7 - 19
No
Modem Board.
IC203-2, 1 CN201-2
No