Mitsubishi Electric MXZ-2D33VA Service Manual page 149

MXZ-3D54VA/3D54VA2/3D68VA/4D72VA
1. Disconnect the lead wire leading to the compressor.
2. 3 minutes after turning ON the power supply, start EMERGENCY
OPERATION in HEAT mode.
Is there voltage of 230 VAC between pin1
and pin2 at connector CN712?
Yes
Turn OFF the power supply.
Disconnect the connector CN712.
Is there normal resistance
to R.V. coil? (Refer to 11-5.)
Yes
Replace the 4-way valve.
1. Disconnect the lead wire leading to the compressor.
2. 3 minutes after turning ON the power supply, start EMERGENCY
OPERATION in COOL mode.
Is there voltage of 230 VAC between pin1 and
pin2 at connector CN712?
Yes
Replace the outdoor control P.C. board.
OBH626K
Is there voltage 230 VAC
No
between the pin1 and pin3 at
connector CN711?
Replace the outdoor control P.C. board.
No
Replace the R.V. coil.
No
CN711
CN712
No
Yes
Replace the 4-way valve.
149
MXZ-3D54VA/3D54VA2/3D68VA/4D72VA
Outdoor control P.C. board
Replace the noise filter P.C. board.