Communication Error Between Mcu And Outdoor Unit - Samsung AM007FN1DCH/AA Service Manual

4-4-25 Communication Error between MCU and Outdoor Unit

Outdoor Unit Display
Indoor Unit Display -
• Communication Error between MCU and outdoor unit
Judgment Method
• Reference below
Special Cause
1. Inspection Method
MCU Installation Quantity Setup Switch for
Outdoor Unit PCB Compare and check the set values
and the actual MCU installation quantity.
the actually installed MCUs and the set value
of the installation quantity setup
Press the reset key (K3) of the outdoor unit PCB
and check the display module to check the quantity
of MCU which responds to tracking.
Is there any response from the
MCU on the display module during 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?
Check the communication cable which connects the outdoor unit
to the MCU. If there is no peculiarity, connect the MCUs one by
one to find the MCU which interferes with the communication
to check and change the MCU PCB.
❈ Essential Requirements before Changing PCB in Case of Communication Error: Refer to p.4-80
Samsung Electronics
Are the quantity of
switch the same?
Yes
Yes
Yes
No
Correctly set the installation quantity setup switch
of the outdoor unit MCU, and press the reset key (K3)
of the outdoor unit PCB to re-execute tracking.
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 (2 or more units) with the address
No
If there is no peculiarity in the address, then check
the communication cable and change the MCU PCB.
Change the communication cable and the connector
of the outdoor PCB, and then change the PCB.
Troubleshooting
incorrectly set.
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