Main Pcb Has No Power Phenomenon - Samsung AM080 XV Series Service Manual

4-3-2 Main PCB has no power phenomenon

Outdoor unit display Main PCB has no power phenomenon (7-seg does not blink)
Judgment Method Hub PCB power and connection wire to detect.
CN96 on HUB PCB
Connector check
- 1pin to 4pin : DC 12V
Method
- 9pin to 4pin : DC 5V
∙ HUB PCB connector wire defects and the connection is not.
∙ Main PCB defective.
Cause of problem ∙ Hub PCB defective.
∙ High pressure switch operation
∙ Water hub PCB defective. CN96 on HUB PCB
1. Cause of problem
Power On
Did the first EMI PCB Fuse
become short-circuit?
Did the high pressure
switch become short-circuit?
Is the rated
voltage of CN70(1pin to 3pin)
connector of the HUB PCB is supplied to
within ± 10%?
Is the HUB PCB LED lighted up?
Is the communication wire of
MAIN/HUB connected?
Replace the MAIN PCB.
Samsung Electronics
Yes
Yes
Yes
Yes
Yes
Yes
No
No
Check the refrigerant overcharge.
Replace if there is no abnormality.
No
Check the rated input voltage range
on main terminal block. (R/S/T/N).
Check the short-circuit of HUB PCB.
No
Replace HUB PCB if there is abnormality.
Connect the communication wire to the CN96
No
connector on the HUB PCB.
Troubleshooting
Replace the EMI PCB.
4-17