Mitsubishi Electric MXZ-32SV Service Manual page 29

Outdoor unit does not operate. (LED display: display OFF)
A A Check of power supply
Start
Check the connecting of main circuit parts and connector (CN501: I.P.M P. C. board,
CN 801: Electronic control P. C. board, CN554: relay P. C. board)
Turn on power supply
Is there voltage of 220V AC - 240V AC
in the power supply terminal block?
Yes
Is there voltage of 310V DC - 340V DC
across the smoothing capacity?
Yes
Replace the electronic control P. C. board.
Outdoor unit does not operate. (LED display: 0 0 0 0 )
B B Check of serial signal
Start
1. Check the indoor unit with referring to the indoor unit service manual
2. Turn off the power supply of the indoor and outdoor unit and return the indoor/ outdoor unit
connecting wire to former original.
3. Check the connection of indoor/ outdoor unit connecting wire in the outdoor unit terminal block,
and check the connection of the connector (CN601: unit A, CN 602: unit B, CN603: unit C,
CN604: unit D) in the electronic control P. C. board
4. Disconnect the lead wire to the compressor. Turn on the power supply (indoor/ outdoor unit)
3 minutes later, EMERGENCY OPERATION starts.
Is there voltage of 5V DC - 10V DC between
No. 3 (+) and N (-) in the outdoor terminal block.
Yes
Recheck a connected circumstance of the indoor/ outdoor unit connecting wire.
No
Check the power supply cable.
Is there voltage of 220V AC - 240V AC
No
across the output cable (LD63, LD64)
in the noise filter P. C. board?
Yes
Is there voltage of 220V AC - 240V AC
across the input terminal part in the
diode module (DS61)?
Yes
Check the main circuit parts
and replace it.
No
Replace the electronic control P. C. board.
29
Replace the noise
No
filter P. C. board
No Replace the current
limiting resistor.
w When replacing, check the
connection of connector
CN720 in the outdoor
electronic control P. C.
board