Noise - Mitsubishi Electric MSH-XV07UV Service Manual

When OPERATION INDICATOR lamp flashes 3-time.
Indoor fan motor doesn't operate.
Check of indoor fan motor
A
No
Are lead wires connected?
Re-connect the lead wires.
Disconnect lead wires from connector CN211 on indoor electronic control P.C. board.
Measure resistance between lead wires No.1 and No.5 and then No.3 and No.5.
Indoor unit operates by pressing the EMERGENCY OPERATION switch, but doesn't operate with the remote controller.
Check of remote controller and receiver P.C. board
B
wCheck the remote controller is exclusive for this air conditioner.
Switch on the remote controller.
Is LCD display on the remote con-
troller displayed?
Yes
Remove batteries, then set them back and
press the RESET button. Check if the unit
operates with the remote controller.
Does the unit operate with the
remote controller?
Yes
OK
Turn OFF the power supply.
Check connector CN211 visually.
Yes
Is resistance 0 (short circuit) or ∞ (open circuit)?
Yes ( 0 or ∞ )
Repair or replace the indoor fan motor.
No
Replace the batteries.(Refer to page 40.)
(not clear)
No
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
button is pressed.
Is the voltage approx. 4V DC?
Replace the receiver P.C. board.
Is soldered point of the connector
Turn ON the power supply. Stop it if the unit oper-
ate. Insert screwdriver into air outlet to rotate
indoor fan motor slowly for 1 revolution or over, and
No
measure voltage No.2(+) and No.3(-) on CN121.
(others)
No
Replace the indoor electronic control P.C. board.
No
Yes
Yes
No
Yes
No(5V or 0V DC)
44
No
correctly soldered?
Yes
Re-solder it.
Does voltage repeat 0V DC and 5V DC?
Yes
Replace the remote controller.
• Re-install the unit away from lights.
• Attach a filter on receiving part.
(+)
(–)
and No.5 when the remote controller
Replace the indoor electronic control
P.C. board.