Troubleshooting Problems With Outdoor Unit Transmission Power Supply Circuit - Mitsubishi Electric R410A Service Handbook

[8-12 Control Circuit (YLMU) ]
8-12-2 Troubleshooting Problems with Outdoor Unit Transmission Power Supply
Circuit
1) PUHY-P72, P96, P120, P144, P168YLMU
Check the voltage at the indoor/outdoor
transmission terminal block (TB3) of outdoor unit.
DC 24 ~ 30 V
Check the voltage at TB3 after removing transmission line from TB3.
DC 24 ~ 30 V
Check whether the male connector is connected to
the female power supply connector (CN40).
NO
Check voltage of terminal block for centralized control (TB7).
DC 24 ~ 30 V
Check voltage of TB7 by removing transmission line from TB7.
DC 24 ~ 30 V
Check the voltage between No.1 and No.2 pins of the
CNS2 on the control board.
DC 24 ~ 30 V
Check the voltage between No.1 and No.2 pins of the
CN102 on the power supply board for the transmission line.
DC 24 ~ 30 V
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.
DC270 ~ 356V
Check the noise filter fuse F4 .
Fuse F4 on the noise filter board is blown.
Check fuse F5.
Fuse F5 is blown.
Check the voltages among TB22 and TB23 on the
noise filter
AC41 4 ~ 506V
Check the voltage between L2 and L3 at the power supply
terminal block TB1.
AC414 ~ 506V
HWE14080
YES
NO
YES
NO
Connected
YES
YES
NO
NO
YES
NO
YES
NO
YES
NO
NO
YES
DC270 ~ 356V
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
Check whether the transmission line is disconnected,
check for contact failure, and repair the problem.
Check if the indoor/outdoor transmission line is not
short-circuited, and repair the problem.
Check the wiring between the control board and power supply board for the transmission line
(CN62, CNPS, CN102 and CNIT), and check for proper connection of connectors.
YES
Is there a wiring
Fix the wiring and connector disconnection.
error or a connector
disconnection?
Check for shorted transmission line or power feed
collision for centralized control.
Replace the control board.
Check the wiring between the control board and power supply board for the transmission line
(CN62, CNPS, CN102 and CNIT), and check for proper connection of connectors.
YES
Is there a connector
Fix the connector disconnection.
disconnection?
NO
Check the voltage between No.5 and No.2 pins of the CNPS
on the control board.
YES
Is the voltage
measurement between Replace the M-NET board
4.5 and 5.2 VDC?
Replace the control board.
Replace the M-NET board
Disconnect the noise filters CN4 and CN5, and then replace fuse F4 on the noise filter
board, then turn the power on.
YES
Fuse F4 on the
Replace the noise filter.
noise filter board is blown.
NO
Connect the noise filter CN4, and then turn the power on.
YES
Fuse F4 on the
Replace the control board.
noise filter board is blown.
NO
Replace the M-NET board
Pull out CN4 and CN5 on the noise filter, replace fuse F5, and turn on the power.
YES
Replace the noise filter.
Fuse F5 is blown.
NO
Connect the noise filter CN4, and then turn the power on.
YES
Replace the control board.
Fuse F5 is blown.
NO
Replace the M-NET board
Replace the noise filter.
Replace the noise filter.
Check and fix any power supply wiring and main power supply problems found.
- 292 -
Turn on the
power again.
GB