Indoor Fan Motor Check Procedure - Mitsubishi Heavy Industries FDT100VNAWVH Service Manual

blocks ② and ③ oscillating between
DC 0 and 20V?
Indoor electrical components
are normal.

2) Indoor fan motor check procedure

a) Indoor unit PCB output check
i)
ii)
iii)
DC several V
(4-6 V)
CNU
b) Fan motor resistance check
Measuring point
① − ③
−
④ − ③
−
(vii) Inspection procedure for blown fuse on the indoor unit PCB
( )
Faulty part, other than
fan motor
Replace the faulty part and the
fuse. Test-run then the unit for
checking.
Replace the indoor unit PCB and the fan motor. Check then the operation.
YES
(–)
GND
DC15V
⑥ ⑤ ④ ③
⑥ ⑤ ④ ③
FM
i
Resistance when normal
M
k
Is the fuse blown on the indoor unit
PCB?
YES
YES
Is there any faulty part (fan motor, etc)?
YES (Fan motor is faulty.)
Is there any damage on the internal circuit
of fan motor?
Check the resistance value to judge.
Replace the fuse on the indoor unit
PCB. When the operation is checked
without connecting the fan motor
connector, does the fuse blow?
YES
Replace indoor unit PCB.
DC 308-336V
Indoor unit PCB
② ①
② ①
NO
Go to the inspection procedure for electric
equipment of indoor unit.
NO
Replace the fuse, and check the operation.
NO
Replace the fan motor, and check the operation.
66
- -
'19 • PAC-SM-309
① ④ ⑤
Measuring Voltage range when
point normal
① − ③
④ − ③
⑤ − ③
-
-