MXZ-SM42NAMHZ Service Manual

116
OCH789
Check method of power circuit board
Is the voltage of main incoming power
208/230 V AC ±10%?
• Check the breaker and power supply.
Is the voltage of CNAC (RD) on
multi controller circuit board
208/230 V AC ±10%?
• Check wiring.
• Replace power circuit board.
Is the voltage of CNDC(PK) on multi
board 290–380 V DC?
• Check wiring.
• Check power circuit board.
• Retry after the temperature of the PTC1,2
drops to 257°F[125°C] or less
Note: To check the voltage of the parts on this board with a multimeter is difficult due to its location.
Test points are limited.
Yes
Yes
Yes
Yes
No
No
No
No
Is the voltage between M1 and M2 on
TB3 (M-NET transmission) 24–30 V DC?
• Check wiring.
• Check M-NET power circuit board.
No
Turn off the incoming power supply
and check the resistance of PTC1,2 on
the Power circuit board.
PTC1,2 = open ?
Yes (open)
•Replace the power circuit board and check
52C-relay,wiring,power circuit board .
• Check wiring.
• Check model setting switch SW4 on the
multi controller board.
• Replace power board.
No
(normal)
Power circuit board check
Normal
Yes
Is the voltage of the compressor
(U-V, U-W and V-W) balanced?
Power supply
52C relay
Bus bar voltage
(DC)
COMP (Hz)
PAM
OFF
OFF
ON
OFF
ON
0Hz
ex. 48 Hz
0V
290/325 V DC
360–380 V DC
ON
208/230 V AC
min Hz
290/325 V DC
OFF
TIME CHART
power on start stop
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
COMP
U-V 10–180 V AC
V-W 10–180 V AC
W-U 10–180 V AC
CNDC
(PK)
290–380 V DC
GND
1
3
Power suppl
y
fo
r
multi controller
circuit board
1
3
CNAC
(RD)
1
Multi controller
circuit board
M-NET power
circuit board
208/230 V AC
± 10%
L1
L2
TB1
208/230 V AC
±10%
3
5
CN1
(WH)
208/230 V AC
10%
Power circuit board
Noise filter circuit board
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