MXZ-SM36NAMHZ Service Manual

117
OCH789
Check method of M-NET power circuit board
COMP
U-V 10–180 V AC
V-W 10–180 V AC
W-U 10–180 V AC
1
3
CNAC
(RD)
Multi controller
circuit board
208/230 V AC
±
10%
1
M-NET power
circuit board
L1
L2
TB1
208/230 V AC
±10%
3
5
CN1
(WH)
208/230 V AC
10%
Multi controller circuit board
CN2 (RD)
15V
15V
GND(15V)
GND(15V)
15V
Signals
Signals
7
6
5
4
3
2
1
Power supply for
Inverter gate drive
Power supply for
PAM gate drive
Multi controller circuit board
CNDC
(PK)
290–380 V DC
GND
1
3
Power suppl
y
fo
r
multi controller
circuit board
Power circuit board
Normal
24–30 V DC?
• Correct the short circuit point on
the M-NET transmission line.
24–30 V DC?
Is the incoming main voltage
208/230 V AC ±10%?
• Check wiring.
• Replace M-NET power circuit board.
• Check breaker and incoming power supply.
• Check power circuit board.
• Check wiring.
Check the voltage between M1 and M2 on the
transmission terminal block TB3.
Disconnect the branch box - outdoor transmission wiring
from the terminal block TB3 , and check the voltage
between M1 and M2 on TB3 again.
* 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 )
No
Yes
(208/230 V AC )
No
Yes
(24–30 V DC )
M-NET power circuit board check
Power circuit board
1
3
CNAC1(WH)
Multi controller circuit board
M1 M2
CNS1
(RD)
2 1
CN102
(WH)
TB3
4 3 2 1
208/230 V AC
±10%
NI
LI
208/230 V AC
±10%
CN1
CN2
24–30 V DC
24–30 V DC (Non-polar)
To indoor unit
M-NET power circuit board
L2
L1
TB1
MXZ-SM36NAM-U1
MXZ-SM48NAM-U1