Samsung AQ18VBA Service Manual page 32

12-2 Fault Diagnosis by Symptom
12-2-1 No Power (completely dead)-Initial diagnosis
1. Checklist :
1) Is input voltage normal?
2) Is AC power linked correctly?
3) Is input voltage of DC regulator IC KA7805 (IC02) normal? (11VDC-12.5VDC)
4) Is output voltage of DC regulator IC KA7805 (IC02) normal? (4.5VDC-5.5VDC)
2. Troubleshooting procedure
Unplug the power cord and
plug it after 30 seconds
Power Button on the
remote control unit to operate the
Check the indoor unit
2 wires of power cord are
connected correctly to the
terminal block and
the fuse on the control board is normal.
FUSE(F701) : T3.15[A]/250[V]
Check the output of
SMPS on the control board.
Input power: AC230±15%[V]
IC02 Input: DC12[V]
IC02 output: DC5[V]
 Check the setting temperature
Samsung Electronics
Press the
air conditioner
does not operate
control board
Yes
Check whether
control board.
Yes
Check whether
Yes
Yes
operate
Check the display board
No
Reconnect wires correctly
No
No
PCB should be replaced
Replace fuse
12-2