Check Of Indoor Electronic Control P.c. Board; Check Of Outdoor Thermistors - Mitsubishi Electric MSZ-G09SV Service Manual

The unit doesn't operate with the remote controller.
Also, the OPERATION INDICATOR lamp doesn't light up by pressing the EMERGENCY OPERATION switch.

Check of indoor electronic control P.C. board

I
Check both "parts side" and "pattern side" of indoor
electronic control P.C. board visually.
Turn OFF the power supply.
Remove indoor fan motor connector CN211 and
vane motor connector CN151from the indoor electronic
control P.C. board and turn ON the power supply.
Does the unit operate with the remote controller?
Does the OPERATION INDICATOR lamp light up
by pressing the EMERGENCY OPERATION switch?
No
Replace the vane motor.
Turn OFF the
power supply.
Is winding resistance
of vane motor 0 "?
Be sure to check both resistance.
Is winding resistance
of fan motor 0 "?
Replace the fan motor .
When OPERATION INDICATOR lamp flashes 6-time.
The thermistors in the outdoor unit are abnormal.

Check of outdoor thermistors

J
Disconnect the connectors CN 641 and CN 642 from the outdoor electronic control P.C. board.
(Check the characteristics of each thermistor.)
Defrost thermistor RT61
Measure
resistance
between CN
6411 and 2.
Discharge
temperature
thermistor RT62
Measure
resistance
between CN
6413 and 4.
Fin temperature
thermistor RT64
Measure
resistance
between CN
6421 and 2.
Fuse (F11)
Indoor electronic
Yes
control P.C. board
Turn OFF the
power supply.
Yes
No
Be sure to check both fuse
and varistor in any case.
No
Yes
1 Connect CN 641 and
2 Disconnect the
Does the
resistance of the
Yes
thermistor have the
characteristics on
page 92?
No
Replace the
thermistor.
Varistor (NR11)
Indoor electronic
control P.C. board
1
3
Replace the fuse.
Yes
No
Is fuse (F11) blown?
No
Is varistor (NR11) burnt?
Yes
Replace the varistor.
CN 642.
connector between
the compressor and
transistor module. Replace the outdoor
electronic control
P.C. board.
Turn ON the
power supply to
indoor unit and Does the unit
operate 10 minutes
press the
EMERGENCY or more?
OPERATION
switch.
Is LED in the
outdoor electronic
control P.C. board
flashing 5 minutes?
Reconnect the
connector
79
Thermal fuse connector
N
2
3
Terminal
Replace the indoor
block
electronic control
P.C. board.
Measure the
resistance
between
1
CN201 on
the indoor
Is resistance approx. 0"?
electronic control
N
P.C. board and
on the terminal
block with the
Replace the fuse (F12).
tester.
No
Yes
Yes
No
Yes
No (∞)