Mitsubishi Electric MXZ-4C36NAHZ Technical & Service Manual page 112

Check method of power circuit board
Power circuit board check
Is the voltage of main incoming power
208/230 V AC ±10%?
Yes
Is the voltage of CNAC (RED) on
multi controller circuit board
208/230 V AC ±10%?
Yes
Is the voltage between M1 and M2 on
TB3 (M-NET transmission) 24–30 V DC?
Yes
Is the voltage of CNDC(PNK) on multi
board 290–350 V DC?
Yes
Is the voltage of the compressor
(U-V, U-W and V-W) balanced?
Yes
Normal
Multi controller circuit board
CN52 (RED)
13V DC
52C relay
drive signal
GND
16V
Power supply for
16V
Inverter gate drive
GND(16V)
Power supply for
GND(18V)
18V
PAM gate drive
Signals
Signals
Power supply for 290–350 V DC
multi controller
GND
circuit board
OCH573E
Note: To check the voltage of the parts on this board with a tester is difficult due to its location.
Test points are limited.
No
No
No
Turn off the incoming power supply
No
and check the resistance of PTC1,2 on
the Power circuit board.
PTC1,2 = open ?
Replace Noise filter board and check
52C-relay,wiring,power circuit board .
No
TIME CHART
Power supply
52C relay
COMP (Hz)
Bus bar voltage
(DC)
PAM
1
3
7
6
5
4
3
2
1
CN2 (RED)
1
3
CNDC
(PNK)
COMP
Check wiring.
Replace power circuit board.
Check wiring.
Check M-NET power circuit board.
No
Check wiring.
(normal)
Check power circuit board.
Retry after the temperature of the PTC1,2
drops to 257°F[125°C] or less
Yes (open)
Check wiring.
Check model setting switch SW4 on the
multi controller board.
Replace power board.
ON
OFF
ON
OFF
ex. 48 Hz
0Hz
330–350 V DC
290/325 V DC
0V
ON
OFF
power on starts
52C
PTCs
(relay)
U-V 10–180 V AC
V-W 10–180 V AC
W-U 10–180 V AC
Check the breaker and power supply.
208/230 V AC
min Hz
290/325 V DC
OFF
stop
Multi controller
circuit board
CNAC
(RED)
208/230 V AC
10%
1
3
M-NET power
circuit board
1
3
208/230 V AC
10%
5
CN1
(WHT)
L1
L2
208/230 V AC
TB1
10%