Samsung AVMKH020EA4 Service Manual page 199

Troubleshooting
11-2-9 Communication error after the completion of tracking
Outdoor unit display
Indoor unit display
Judgment method
Causes
Check the display part with pressing
the rest key(K3) of the outdoor unit PCB.
Is there any response
of the indoor unit at the
display on tracking?
Remove the communication wire
connecting from the outdoor unit to the
indoor unit, and then measure 2 wires
of the outdoor unit with scope.
between both wires square wave
Check the communication wire connecting from the
outdoor unit to the indoor unit. If there is no defect,
search the indoor unit that interrupts the
communication by connecting the indoor unit
one by one. And after check a wire, displace the
+0.7V
-0.7V
11-13
(Operation) (Timer)
- When it is not communicated between the indoor unit and outdoor unit during the operation
- Communication error between the indoor unit and outdoor unit
Yes
Yes
Is the voltage
over DC0.7V?
Yes
indoor unit PCB.
(Fan) (Filter)
No
Search for the indoor unit displayed the
communication error after 2 minutes, and check
the duplication of PCB address setup.
(The communication error is occurred
due to address duplication.)
In this case, the communication error is occurred at
the every indoor unit (over 2ea) set wrong address.
If there is no defect in address, replace the
indoor unit PCB after check the communication wire.
No
After check the communication wire
and connecter of the outdoor unit PCB,
GOOD
(Removing frost)
replace the PCB.
BAD
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