Trouble Shooting By Phenomena; When It Is Not Power On - Samsung APH180HD Service Manual

5-3 Trouble shooting by phenomena

5-3-1 When it is not Power on.(When it is not display)
1) Trouble cause
When the power voltage is out the operating range or the power cable contact is bad.
1
The transformer is defect or it's connection is bad.
2
The fuse of main PCB is broken or the PCB with a defect.
3
4 The panel PCB has it's defect.
• The knob switch with a poor assembly, V.F-display defect.
2) Check items
1 Is the power voltage normal?(AC 187V~AC 253V)
2 Is the contact of power cable good?
3 Is the power fuse(F701, F702) AND PCB fuse(F101)not disconnected?
4 Is the contact of connector at primary and secondary side of power transformer?
5 Is the output voltage of IC08(KA7812) normal?(DC 11.5~DC 12.5V)
6 Is the output voltage of IC09(KA7805) normal?(DC 4.5~DC 5.5V)
7 Is the connection of harness(wire connector- c o n t rol)of main PCB panel good?
3) Sequence of check
Tu rn off the power, and then turn it on in 5 seconds.
Is the display part on dose the door operate
when pressing the start key?
Is the voltage of the power input part(CN71 red-white)
AC 187~AC 253V?
Is the secondary voltage of power transformer correct?
blue-white:AC14~17V,red-red:AC4~5V black-white:AC14~17V
Is the output voltage of IC08, and IC09 normal?
(IC08=12V, RIC09=5V)
Dose the remocon receive the singnal correctly?
Replace it due to the defact of main PCB.
Samsung Electronics
N
Y
Y
Y
N
Y
Normal operation of set.
N
Check the connection harness of indoor and
replace.
N
Check the power trancsfornmer and replace it.
N
Check the main PBC and replace it.
N
Check the knob key.
5-3