Mitsubishi PUHY-EP250 - Troubleshooting Problems with Outdoor Unit Transmission Power Supply Circuit

[8-10 Control Circuit ]
- 245 -
HWE12050 GB
8 Troubleshooting Based on Observed Symptoms
8-10-2 Troubleshooting Problems with Outdoor Unit Transmission Power Supply
Circuit
Check the voltage between No.1 and No.2 pins of the
CNS2 on the control board.
Check the wiring between the control board and M-NET board
for the transmission line (CN62, CNPS, CN102 and CNIT),
and check for proper connection of connectors.
Check the wiring between the control board and M-NET board
for the transmission line (CN62, CN
PS, CN102 and CNIT),
and check for proper connection of connectors.
Is there a wiring
error or a connector
disconnection?
Check the voltage between No.5 and No.2 pins of
the CNPS on the control board.
Is the voltage
measurement between
4.5 and 5.2 VDC?
Is there a connector
disconnection?
Fix the connector disconnection.
Replace the M-NET board
Replace the control board.
Replace the M-NET board
Replace the M-NET board
Replace the noise filter.
Connect the noise filter CN4, and then turn the power on.
Replace the noise filter.
Replace the noise filter.
Check and fix any power supply wiring and main power
supply problems found.
Disconnect the noise filters CN4 and CN5, and then
replace F4, then turn the power on.
Fix the wiring and connector
disconnection.
Check for shorted transmission
line or power feed collision for
centralized control.
Replace the control board.
Check the voltage between No.1 and No.2 pins of the
CN102 on the M-NET board for the transmission line.
Check the voltage between No.1 and No.3 pins of
the noise filter CN4.
Check the voltage between No.1 and No.3 pins of
the noise filter CN5.
Check the noise filter F4 fuse.
Check the voltages among TB22 and TB24 on the
noise filter.
Check the voltage between L2 and N at the power supply
terminal block TB1.
24 ~ 30 VDC
24 ~ 30 VDC
24 ~ 30 VDC
279 ~ 374 VDC
279 ~ 374 VDC
F4 blown
F4 blown
F4 blown
198
~ 264 VAC
198
~ 264 VAC
24
~ 30 VDC
Turn on the
power again.
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
YES
NO
Check the voltage at the indoor/outdoor
transmission terminal block (TB3) of outdoor unit.
24 ~ 30 VDC
24 ~ 30 VDC
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).
Connected
Check voltage of terminal block for centralized control (TB7).
Check voltage of TB7 by removing transmission line from TB7.
Check if the indoor/outdoor transmission line is not
short-circuited, and repair the problem.
Check whether the transmission line is disconnected,
check for contact failure, and repair the problem.
Replace the control board.