Mitsubishi Electric MXZ-SM72TAM-U1 Service Manual page 97

8-7-4. Check method of power circuit board
Power circuit board check
Is the voltage of main incoming power
208/230 V AC ±10%?
Is the voltage of CNAC (RD) on multi
controller circuit board 208/230 V AC ±10%?
Is the voltage between M1 and M2 on TB3
(M-NET transmission) 24–30 V DC?
Is the voltage of CNDC(PK) on multi board
290–380 V DC?
Is the voltage of the compressor (U-V, U-W
and V-W) balanced?
Multi controller circuit board
{
Power supply for
multi controller
circuit board
Power supply for
inverter gate drive
Power supply for
PAM gate drive
M-NET power
circuit board
208/230 V AC ± 10%
OCH800A_97
Yes
Yes
Yes
Yes
Yes
Normal
1
290-380 V DC
GND
3
CNDC
(PK)
7
{ 15 V
6
15 V
GND (15 V)
5
{
4
GND (15 V)
15V
3
2
Signals
Signals
1
CN2
(RD)
CN1
(WH)
1
3
208/230 V AC ± 10%
5
1
3
CNAC
(RD)
Note: To check the voltage of the parts on this board with a
multimeter is difficult due to its location.
Test points are limited.
No
• Check the breaker and power supply.
No
• Check the wiring.
• Replace the power circuit board.
No
• Check the wiring.
• Check the M-NET power circuit board.
No
• Check the wiring.
• Replace the power circuit board.
• Check the wiring.
No
• Check model setting switch SW4 on the multi
controller board.
• Replace power board.
Noise Filter circuit board
L3
L2
L1
Multi controller
circuit board
Resistor: RS
Power circuit board
U-V: 10-230 V AC
V-W: 10-230 V AC
COMP
W-U: 10-230 V AC
208/230 V AC ± 10%