Fax; Fax/Telephone Precautions - Ricoh B174 Service Documentation

TROUBLESHOOTING

4.3.2 FAX

FAX/TELEPHONE PRECAUTIONS

Problem
TEL LINE CANNOT
BE ENGAGED (NO
DIAL TONE)
Tone dial is not
possible
Tone dial is possible
but not pulse dial
Defective fax
transmission
Defective automatic
fax reception
B174
Items to be Checked.
• When you press the "OHD" key:
a) Check the line cord connection.
b) Check the MAIN LIU harness,
and CN1 (LIU PBA).
c) Check the relay operation of the
LIU PBA: Is the control signal of
CN18 (main) low?
• Check CN18 (main PBA), MAIN-
LIU harness, and CN1 (LIU PBA)
• Check DP control signal of CN18-
11 of MAIN PBA and the circuit
around R15. U6 and Q2 of Liu
PBA.
• Check CN18 (main PBA), MAIN
LIU harness, and CN1 (LIU PBA).
• Is the external phone off hook?
• Check 'hook off' : Refer to 'TEL
LINE CANNOT BE ENGAGED'
above.
• Check the transmission path:
Check output of CN20-3.4 and
T2-4(LIU PBA).
• Check the reception path: Check
output CN1-1 (LIU PBA) and input
of CN18-1 (main PBA).
• Is the ring detected?
Check the ring signal at CN1-9
(LIU PBA).
• Refer to '"Defective
Transmission".
a) Insert it correctly into the
b) Replace defective parts.
c) Replace the main PBA
Replace the LIU PBA if high
but the phone line cannot
be connected.
• Replace defective parts.
• Replace the LIU PBA.
• Replace defective parts.
• Replace the LIU PBA if
low.
• Refer to 'TEL LINE
CANNOT BE ENGAGED'
above.
• Replace the main PBA, if
abnormal.
• Replace the LIU PBA if
CN1-1(LIU PBA) is not
confirmed.
• Replace the main PBA if
CN20-1(MAIN PBA) is
not confirmed.
• Replace the LIU PBA if it
cannot be checked.
• Refer to "Defective
Transmission".
4-6
How to Solve
connection jack called
"Line".
IF the control signal of
N18 (main) is high.
SM