Samsung sf150t Service Manual page 30

Troubleshooting
6-11. No Dial Tone
Start
Press
OHD/V.REQ.
Dial tone ?
OK
Lift Handset
Dial tone ?
NG
Check / Replace:
Handset cord
Handset
Hook Switch
LIU U201
LIU Board
Return
machine to
Customer
SF150T
Use a phone to check
service at wall jack
NG
Service OK ?
OK
Replace U3
Test
NG
Telephone
Cord
OK
N
Y
Main PCB
L
U7-54
CML1
H
Main PCB
OK
U3-29, 31
SPK_OUT
NG
Replace
Telephone Cord
Request
Telephone
Service
Check/Replace:
Speaker
Main Board U14
P4, 205, 206
6-15