Mitsubishi Electric MXZ-SM36NAM2 Technical & Service Manual page 115

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?
Normal
MXZ-SM60NAM2-U1
MXZ-SM36NAMHZ2-U1
MXZ-SM42NAMHZ2-U1
MXZ-SM48NAMHZ2-U1
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)
1
Power supply for 290–380 V DC
multi controller
GND
3
circuit board
CNDC
(PK)
OCH810A
Note: To check the voltage of the parts on this board with a multimeter is difficult due to its location.
No
Yes
No
Yes
No
Yes
Turn off the incoming power supply
No
and check the resistance of PTC1,2 on
Yes
•Replace the power circuit board and check
52C-relay,wiring,power circuit board .
No
Yes
TIME CHART
Power supply
52C relay
COMP (Hz)
Bus bar voltage
(DC)
PAM
Power circuit board
7
6
5
4
3
2
1
Test points are limited.
the Power circuit board.
No
• Check wiring.
(normal)
• Check power circuit board.
PTC1,2 = open ?
• Retry after the temperature of the PTC1,2
Yes (open)
ON
OFF
ON
OFF
ex. 48 Hz
0Hz
360–380 V DC
290/325 V DC
0V
ON
OFF
power on start
Noise filter circuit board
U-V 10–180 V AC
V-W 10–180 V AC
W-U 10–180 V AC
COMP
115
• Check the breaker and power supply.
• Check wiring.
• Replace power circuit board.
• Check wiring.
• Check M-NET power circuit board.
drops to 257°F[125°C] or less
• Check wiring.
• Check model setting switch SW4 on the
multi controller board.
• Replace power board.
208/230 V AC
min Hz
290/325 V DC
OFF
stop
Multi controller
circuit board
208/230 V AC
± 10%
208/230 V AC
CNAC
(RD)
1
3
10%
M-NET power
circuit board
1
3
5
CN1
(WH)
L1
L2
208/230 V AC
TB1
±10%