Mitsubishi Electric MS-A08ND, Service Manual

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14
Yes
B B
Check of remote controller and receiver P.C. board
w
Check if the remote controller is exclusive for this air conditioner.
Replace the batteries.
(Refer to 8-1.4.)
Turn on a radio to AM and press switch on
the remote controller.
Is noise heard from radio?
Are there any fluorescent lights of
inverter or rapid-start type within the
range of 1m?
Measure the voltage between receiver P.C. board connector CN302 No.3
(-)
and No.5
(+)
when the remote controller button is pressed.
Is the voltage approx. 4V DC?
Replace the indoor electronic control
P.C. board
Replace the power monitor, receiver P.C.board.
Replace the remote controller.
●
Reinstall the unit away from lights.
●
Attach a filter on receiving part.
Switch on the remote controller.
Is LCD display on the remote con-
troller visible?
Remove batteries, then set them back and
press the RESET button.
Check if the unit operates with remote con-
troller.
Yes
Does the unit operate with remote
controller?
Yes
OK
No
(not clear)
Yes
No
No
No(5V or 0V DC)
No
A A
Check of indoor fan motor
Turn OFF the power supply.
Check connector CN211 visually.
Disconnect lead wires from connector CN211 on the indoor electronic control P.C. board.
Measure resistance between lead wires: No.1 and No.5 and then No.3 and No.5.
Are lead wires connected?
Is soldering point of the connector
correctly soldered?
Resolder it.
Yes
No
No
Yes
Reconnect the lead wires.
Repair the indoor fan motor.
Is resistance 0 (short circuit) or
∞
(open circuit)?
Yes ( 0 or
∞
)
No
(others)
Insert screwdriver into air outlet to rotate indoor fan
motor slowly for 1 revolution or over, and measure
voltage No.2(+) and No.3(-) on CN121.
Replace the indoor electronic control P.C. board.
Does voltage repeat 0V DC and 5V DC?
Yes
No
When left OPERATION INDICATOR lamp flashes 3-time.
Indoor fan motor doesn’t operate.
Indoor unit operates by pressing the EMERGENCY OPERATION switch, but doesn’t operate with the remote controller.
Yes
8-5. Troubleshooting flow
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