Hitachi RAS-50YH4 Service Manual page 94

6. Check the main P.W.B (power circuit)
Is DC 35V being output
between cathode and
anode of D101?
Yes
Is DC 12V being output?
Yes
Is DC 5V being output?
No
Is ICP2 normal?
Normal if it is less than 1Ω.
Blown (open) if it is 1Ω or more
No
Is ICP1 normal?
Normal if it is less than 1Ω.
Blown (open) if it is 1Ω or more
Replace IC111.
Perform final operation check.
No
No
Yes
– 104 –
Replace ICP2. Check if
shorting has occurred in fan
motor circuit and 35V
interface circuit. If these are
defective, ICP2 will be open
again.
Replace ICP1. Check if
shorting has occurred in the
air deflector motor.
If these are defective, ICP1
will be open again.
Replace REG2. Check the 5V
line: if the 5V line is shorted,
ICP1 will be open again.