Communication Error Between Mcu And Outdoor Unit After Tracking Is Completed - Samsung AM009FN1DCH/AA Service Manual

Troubleshooting

4-4-28 Communication Error between MCU and Outdoor Unit after Tracking is Completed

Outdoor Unit Display
Indoor Unit Display
-
Judgment Method
Special Cause
setup switch
1. Inspection Method
Press the PCB reset key (K3) of the outdoor unit
and check the display module.
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.
Is the voltage between the 2 cables a
square wave with DC±0.7V or more?
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.
❈ Essential Requirements before Changing PCB in Case of Communication Error: Refer to p.4-80
0.7V
0.7V
4-54
Yes
Yes
Good
No
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.
If there is no peculiarity in the address, check
communication and then change the MCU PCB.
No
Inspect the communication cable
and the connector of the outdoor PCB
and then change the PCB.
Defective
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