Mitsubishi Electric MXZ-SM36NAM2 Technical & Service Manual page 116

MXZ-SM36NAM2-U1
MXZ-SM48NAM2-U1
Power circuit board
Multi controller circuit board
15V
Power supply for
15V
Inverter gate drive
GND(15V)
Power supply for
GND(15V)
PAM gate drive 15V
Signals
Signals
CN2 (RD)
Check method of M-NET power circuit board
M-NET power circuit board check
Check the voltage between M1 and M2 on the
transmission terminal block TB3.
24–30 V DC?
Normal
Multi controller circuit board
4 3 2 1
2 1
CN102
CNS1
(WH)
(RD)
24–30 V DC (Non-polar)
TB3 M1 M2
To indoor unit
OCH810A
Multi controller
circuit board
7
6
5
4
3
2
1
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
Yes
(24–30 V DC ) Is the incoming main voltage
208/230 V AC ±10%?
Disconnect the branch box - outdoor transmission wiring
from the terminal block TB3 , and check the voltage
between M1 and M2 on TB3 again.
• Check wiring.
• Replace M-NET power circuit board.
M-NET power circuit board
24–30 V DC CN2
M-NET power
circuit board
1
CNAC
3
(RD)
1
5
208/230 V AC CN1
3
(WH)
10%
208/230 V AC
± 10%
No
Yes
(208/230 V AC )
24–30 V DC?
Yes
(24–30 V DC )
No
CN1 208/230 V AC
±10%
116
L1
L2
208/230 V AC
TB1
±10%
COMP
U-V 10–180 V AC
V-W 10–180 V AC
W-U 10–180 V AC
Multi controller circuit board
1
Power supply for
multi controller
3
circuit board
CNDC
(PK)
• Check breaker and incoming power supply.
• Check power circuit board.
• Check wiring.
• Correct the short circuit point on
the M-NET transmission line.
Power circuit board
208/230 V AC
±10%
NI
1 L2
LI
3 L1
CNAC1(WH)
TB1
290–380 V DC
GND