Troubleshooting - Mitsubishi Electric MS-09SN-C1 Service Manual

10

TROUBLESHOOTING

MS-12SN -
MS-09SN -
C1
MS-12SN -
MS-09SN -
C2
MS-15SN -
MS-10SN -
C1
MS-15SN -
MS-10SN -
C2
10-1. Cautions on troubleshooting
1. Before troubleshooting, check the following:
1) Check the power supply voltage.
2) Check the indoor/outdoor connecting wire for mis-wiring.
2. Take care the following during servicing.
1) Before servicing the air conditioner, be sure to first turn off the remote controller to stop the main unit, and then after
confirming the horizontal vane is closed, turn off the breaker and / or disconnect the power plug.
2) Be sure to unplug the power supply cord before removing the front panel, the cabinet, the top panel, and the electron-
ic control P.C. board.
3) When removing the electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the
components.
4) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.
3. Troubleshooting procedure
1) First, check if the OPERATION INDICATOR lamp on the indoor unit is flashing on and off to indicate an abnormality.
To make sure, check how many times the abnormality indication is flashing on and off before starting service work.
2) Before servicing check that the connector and terminal are connected properly.
3) If the electronic control P.C. board is supposed to be defective, check the copper foil pattern for disconnection and
the components for bursting and discoloration.
4) When troubleshooting, refer to the flow chart and the check table on page 35.
4. How to replace batteries
Weak batteries may cause the remote controller malfunction.
In this case, replace the batteries to operate the remote controller normally.
1 Remove the front lid and insert batteries.
Then re-attach the front lid.
NOTE : If the RESET button is not pressed, the remote controller may not operate correctly.
MS-17SN -
C1
C1
MS-18SN -
C2
C1
MS-24SN -
C1
C1
C2
Lead wiring
Insert the negative pole
of the batteries first.
Check if the polarity of
the batteries is correct.
MU-12SN -
MU-09SN -
C1
MU-12SN -
MU-09SN -
C2
MU-15SN -
MU-10SN -
C1
MU-15SN -
MU-10SN -
C2
Housing point
2 Press the RESET button with tip end of ball point pen
or the like, and then use the remote controller.
RESET button
34
MU-17SN -
C1
C1
MU-18SN -
C2
C1
MU-24SN -
C1
C1
C2