Mitsubishi Electric e Series Service Handbook page 141

[ IX Troubleshooting ]
Control Circuit
-6- Control Circuit
Troubleshooting transmission power circuit of unit
Check the voltage at the internal transmission
terminal block (TB3) of outdoor unit.
Check the voltage at TB3 after removing
transmission line from TB3.
Check whether the male connector is connected to the
female power supply connector (CN40).
NO
Check voltage of terminal block for centralized control (TB7).
Check voltage of TB7 by removing transmission line from TB7.
Check the voltage across pins 3 and 4 of CNPW on the control board.
Check the voltage across pins 1 and 2 of CNPW on the control board.
Check the voltage across pins 1 and 2 of CN600 on the control board.
Check the wiring between the control board and
power-supply board, and also check connectors
CN600 and CNDC for proper connections.
Check the wiring between the noise filter board and
power-supply board, and also check connectors
CN1 and CN100 for proper connections.
Check fuse F4 on the noise filter board.
HWE20010
24-30 VDC
NO
24-30 VDC
NO
Connected
YES
24-30 VDC
NO
24-30 VDC
NO
24-30 VDC
NO
24-30 VDC
NO
10-14 VDC
NO
Any problems with wiring or
loose connectors?
NO
Any problems with wiring or
loose connectors?
NO
Fuse F4 is blown.
NO
A
YES
Check whether the transmission line is disconnected,
check for contact failure, and repair the problem.
YES
Check if the transmission line is not
internal
short-circuited, and repair the problem.
Check the wiring between the control board and
YES
power-supply board, and also check connectors CNPW,
CNPS, CN202, and CNINT for proper connections.
YES
NO
Is there a wiring Fix the wiring and connector
error or a connector
disconnection.
disconnection?
YES Check for shorted transmission
line or power feed collision for
centralized control.
YES
Replace the control board.
Check the wiring between the control board and
YES
power-supply board, and also check connectors CNPW,
CNPS, CN202, and CNINT for proper connections.
YES
Any problems Correct wiring problems, and
with wiring or loose
tighten loose connectors.
connectors?
NO
Check the voltage across pins 4-1 of CNPS on the control board.
NO
YES
Replace the power-supply board.
3.25-3.35 VDC
YES
Replace the control board.
YES
Correct wiring problems, and tighten loose connectors.
YES
Correct wiring problems, and tighten loose connectors.
YES
Disconnect CN1 on the noise filter board,
replace F4, and turn on the power supply.
YES
Fuse F4 is
Replace the noise filter.
blown.
NO
Replace the power-supply board.
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B
GB