Panasonic WH-MXC09J3E8 Service Manual page 170

17.5.21 Indoor-Control Panel Communication Abnormality (H76)
Malfunction Decision Conditions:
During standby and operation of cooling and heating, indoor-control panel error occur.
Malfunction Caused:
1 Faulty connector connection.
2 Faulty control panel.
3 Faulty indoor unit PCB (main).
Troubleshooting:
Check the CN-REMOTE connector connection:
- Turn OFF the power
- Check the connector connection
Is the CN-REMOTE
connector connection normal?
Yes
Check the control panel
cable connection.
Is the control panel cable
connection normal?
Yes
For safety reason and to prevent component breakdown,
always switch off the power before remove and connect the component.
Caution
No
- Connector poor contact
- Correct the connection
No
- Defect in cable connection
- Replace control panel cable
Check the DC voltage from the indoor unit PCB (main):
- Plug out connector from the indoor unit PCB (main)
- Turn ON the power
- Measure the DC voltage pin 1 & 4 of CN-REMOTE
Is the remote controller
(control panel) voltage 5 Vdc
(pin 1 & 4) generated?
No
170
- Defect in remote controller
Yes
(control panel)
- Replace the remote
controller (control panel)
- Defect in indoor unit PCB
(main)
- Replace the indoor unit PCB
(main)