Service manual

Samsung Electronics 8-6
8-2 FAX/TELEPHONE Precautions
PROBLEM ITEMS TO BE CHECKED HOW TO SOLVE
TEL LINE CANNOT
BE ENGAGED (NO
DIAL TONE)
Cannot MF dial.
MF dial is possible
but not DP dial.
Defective fax
transmission
Defective automatic
fax reception
• When you pick up the handset:
➀
Check line cord connection and
P3(LIU) connection.
➁
Check hook switch of H/B Cradle
and D2(LIU) connection.
➂
Check the circuit around R2, Q1
and Q2 of LIU PBA.
➃
Can’t you hear dial tone though the
line is engaged?
• When you press “OHD” key:
➀
Check line cord connection.
➁
Check U7(main PBA), main LIU
harness, and P1(LIU PBA).
➂
Check relaying operation of LIU
PBA : Is the control signal of
U18-49(main) high?
• Check U7(main PBA), main-LIU
harness, and P1(LIU PBA)
• Check signals of U16-122, 123.
• Check DP control signal of U3-27 of
LIU PBA and the circuit around R2, Q1
and Q2.
• Check connection of R43 of LIU PBA.
• Check U7(main PBA), main LIU
harness, and P1(LIU PBA).
•
a
Is the external phone hooked off?
b
Is the output of U2-4(LIU PBA) low?
• Check ‘hook off’. : Refer to ‘TEL LINE
CANNOT BE ENGAGED’.
• Check the control signals of U15-122,
123.
• Check transmission path.: Check
output of U15-44(main PBA) and input
of U3-3(LIU PBA).
• Check reception path.: Check output of
U3-40(LIU PBA) and input of
U15-45(main PBA).
• Is the ring checked?
Check ring pattern at U18-84(main
PBA).
• Refer to ‘Defective Transmission’.
•
➀
Insert it correctly into the connection jack
called “line”.
➁
Replace defective parts.
➂
Replace LIU PBA.
➃
Replace the handset.
•
➀
Insert it correctly into the connection jack
called “line”.
➁
Replace defective parts.
➂
Replace main PBA IF the control signal of
U18-49(main) is low. Replace LIU PBA if
high but phone line cannot be connected.
• Replace defective parts.
• Replace main PBA if the signals of U16-
122(LIU_TXD) are abnormal. Replace LIU
PBA if the signals of U16-123(LIU_RXD).
• Replace LIU PBA.
• Replace LIU PBA.
• Replace defective parts.
•
a
Hook on the external phone correctly.
b
Replace LIU PBA if low.
• Refer to ‘TEL LINE CANNOT BE
ENGAGED’.
• Replace main PBA if the signals of
U15-122 (LIU_TXD) are abnormal.
Replace LIU PBA if the signals of
U15-123 (LIU_RXD) are abnormal.
• Replace main PBA, if abnormal.
• Replace LIU PBA if the output of
U3-40 (LIU PBA) is not confirmed.
Check the circuit around U6 (main PBA)
if the input of U21-45 (main PBA) is not
confirmed though the output of
U3-40 (LIU PBA) is confirmed.
• Replace LIU PBA if it cannot be checked.
• Refer to ‘Defective Transmission’.