Check Of Power Supply; Check Of Serial Signal - Mitsubishi Electric MSH09TW Service Manual

Outdoor unit does not operate. (LED display: display OFF)
I I 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 208V AC - 230V AC
in the power supply terminal block?
Yes
Is there voltage of 290V DC - 330V DC
across the smoothing capacitor?
Yes
Replace the electronic control P. C. board.
Outdoor unit does not operate. (LED display:
J J Check of serial signal
Start
1. Check the indoor unit with referring to F How to check mis-wiring and serial signal error.
2. Turn off the power supply of the indoor and outdoor unit and connect the indoor/outdoor unit
connecting wire correctly.
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) in
the electronic control P. C. board.
4. Disconnect the lead wire to the compressor. 3 minutes after turning on the power suppy, start
EMERGENCY OPERATION.
Is there voltage of 5V DC - 10V DC between
No. 3 (+) and 1 (-) in the outdoor terminal block.
No
Recheck a connected circumstance of the indoor/ outdoor unit connecting wire.
(MXZ30TN MXZ30TN2)
No
Check the power supply cable.
Is there voltage of 208V AC - 230V AC
No
across the output cable (LD63, LD64)
in the noise filter P. C. board?
Yes
Is there voltage of 208V AC - 230V AC
across the input terminal part in the
diode module (DS61)?
Yes
Check the main circuit parts
and replace it.
0 0 0 0 )
(MXZ30TN MXZ30TN2)
Yes
Replace the electronic control P. C. board.
89
No Replace the noise
filter P. C. board
Replace the current
No
limiting resistor.
w When replacing, check the
connection of connector
CN720 in the outdoor
electronic control P. C.
board