Mitsubishi Electric MXZ-SM36NAM2 Technical & Service Manual page 114

Check method of multi controller circuit board
Multi controller circuit board check
Fuse check
Check the fuse on multi controller circuit board
Yes
(blow)
Did the fuse blow?
No
Did the fuse (F1 and F2) blow?
No
Is 7seg LED lit?
(SW1: all off)
Yes
(lit)
LED1
Normal
Power
circuit
board
Noise
Filter
Circuit
OCH810A
Disconnect the FAN motor connector and
measure the resistance of connector pins.
Refer to "8-7. HOW TO CHECK PARTS".
Yes (blow)
No (No lit)
Check the voltage from the power circuit
board to CNDC (PK) connector.
LED2
290 to 380 V DC?
• Check wiring.
• Replace multi controller circuit board.
CNDC
(PK)
CNDC
(PK)
1
Conv. 1
3
1
Circuit
3
1 3
3
290-380V DC
CNAC2
(RD)
1
1
3
3
208/230V AC
LI NI
TB1
L1 L2
208/230V AC 10%
Is the fan motor normal?
No
Replace outdoor multi controller circuit board
(MULTI.B.) and the defective fan motor.
Check the SV1, SV2, SS and 21S4 and wiring.
No
Yes
• Check the breaker and main incoming power.
• Check power board.
• Check wiring.
JP50
F1
CNAC
F2
(RD)
10%
114
Yes
Replace outdoor multi controller
circuit board (MULTI.B.).