Troubleshooting
78
Samsung Electronics
4-4-30 Communication Error between MCU and Outdoor Unit after Tracking is Completed
1. Inspection Method
Yes
Press the PCB reset key (K3) of the outdoor unit
and check the display module.
Is the voltage between the 2 cables a
square wave with DC±0.7V or more?
Is there no MCU response at all on the
display module during the tracking?
Remove the communication cable which
connects the outdoor unit to the MCU, and measure
the 2 cables of the outdoor unit with a scope.
Connect the communication cable which connects the
outdoor unit to the MCU again, remove all communication
connectors from the MCU PCB. Connect each unit one by one,
and find the MCU which interferes with communication to
check and change the MCU PCB.
After two minutes, find the MCU which displays
the communication error and check if the PCB address
settings are overlapped. (A communication error occurs
if the indoor unit addresses are overlapped.)
- In this case, a communication error will occur in every
MCU (two or more units) with the address incorrectly set.
Inspect the communication cable
and the connector of the outdoor PCB
and then change the PCB.
0.7V
0.7V
Good
Defective
If there is no peculiarity in the address, check
communication and then change the MCU PCB.
Yes
No
No
❈
Essential Requirements before Changing PCB in Case of Communication Error: Refer to p.4-80
Outdoor unit display
Indoor unit display
Criteria
• Outdoor unit is unable to communicate for two or more minutes during operation (no reception of relocation)
Cause of problem
• Communication error between indoor and outdoor units and setup error of indoor unit installation quantity
setup switch
