Mitsubishi Electric MUZ-HA VF Series Service Manual page 36

HR60/71
Turn OFF the power supply.
Remove indoor fan motor connector CN211
from indoor power P.C. board and vane
motor connector CN151 from the indoor
electronic control P.C. board and turn ON
the power supply.
Does the unit operate with the remote
controller?
Does OPERATION INDICATOR lamp light
up by pressing the emergency operation
switch?
No
Turn OFF the power supply.
Check both "parts side" and "pattern
side" of the indoor power P.C. board
visually.
*1. The fan motor connector's lead wire is red,
whereas is black.
*2. Connect "+" of the multimeter to fan motor
connector's lead wire, and "-" to
wire, otherwise the resistance cannot be
measured properly.
*3. Please replace the fuse after removing the
indoor power P.C. board from the electrical
box.
Measure the resistance of reactor (L111)
or (L112) on the indoor power P.C. board.
Indoor electronic control P.C. board
12 V DC
Indoor power P.C. board
CN211
OBH822H
Measure the resistance between
CN211 and
motor connector.
Measure the resistance of the vane
motor coil.
Yes
Refer to 10-5.
Replace the varistor (NR11)
and fuse (F11). *3
Is the varistor (NR11)
burnt and the fuse (F11)
blown?
Be sure to check both the fuse
and the varistor in any case.
Is the fuse (F11) blown
only?
Measure the resistance between
CN211 (+) and (-) of indoor fan
lead
motor connector. *1, *2
Is the resistance 1MΩ or more?
Replace the fuse (F11). *3
5 V DC
GND
CN10A
Fuse
(F11)
L111
Varistor
or
(NR11)
L112
of the indoor fan
Yes
No
With a multimeter, check the
continuity between the
connector CN201
indoor power P.C. board and
S2 on the terminal block.
No
Yes
Replace the fuse (F11) and the
indoor fan motor. *3
No
Yes
Is the resistance of reactor (L111)
or (L112) approximately 4.3 Ω ?
Yes
Is there approximately 5 V DC between
5 V (+) and GND (-) of the indoor
electronic control P.C. board? Is there
approximately 9 V to 13 V DC between
12 V (+) and GND (-) of the indoor
electronic control P.C. board?
No
Is the connector CN10A on
the indoor electronic control
P.C. board or lead wires
disconnected?
No
Replace the power P.C. board.
36
Short circuit:
Replace the indoor fan motor.
Short circuit:
Replace the vane motor and the indoor
electronic control P.C. board.
Is electricity
conducted? (The
on the
resistance is 0 Ω .) Yes
Replace the terminal block
assembly.
Replace the indoor power P.C. board
and the indoor fan motor.
No
Replace the indoor fan motor.
Yes
Connect the connector CN10A or repair
disconnection.
Yes
No