Hitachi RAF-35NH5 Service Manual page 324

2. Only indoor fan does not operate (others are normal)
Is 25-35V DC being generated
between blue and red of C 10,
C 15 in the "Hi" fan mode?
o
Is the microcomputer fan PWM
output (pin ) ÒHiÓ in the fan
mode or are pulses being output
from it?
o
3. Indoor fan speed does not change (others are normal)
Can the fan be stopped by remote
control?
o
Yes
Is 5V DC being generated
between blue and yellow of C 10,
C 15?
Yes
Perform final operation check.
Yes
The microcomputer fan PWM
output (pin ) is ÒHiÓ.
Perform final operation check.
Yes
Replace the indoor fan motor.
Check according to the proper
o
method for checking the power
circuit.
Replace Q901 or Q903.
Replace the microcomputer.
Yes
Replace the microcomputer.
o
Replace Q901 or Q903.
Replace the microcomputer.
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