TCL TRF-520WEXA+ Service Manual page 27

Common faults of electrical installation
No. Fault phenomenon
The defroster heater
1
in chamber F fails
The grounding
2 resistance is
unqualified
After connecting the
power supply, the
3
whole machine has
no power
Compressor does
4
not start
Cause of failure
The terminal connector is poor
The heating pipe of defroster fails
The fuse of defroster fails
The screws of grounding wire of
compressor are loose
The connector is loose
The master control board fails
The terminal connection is poor
The master control board fails
Compressor fails
Handling method
Check all terminals to ensure their connections are reliable:
Use a multimeter to measure the resistance at both ends of the
heating pipe, which shall be about 280 Ω under normal
conditions:
Measure the two ends of the fuse of defroster with external
meter, and it shall be in on-state:
Check the grounding condition of compressor and tighten the
screws:
According to the physical wiring diagram, check the
connection of the corresponding connection terminals:
Check the power input end of the master control board.
If the input is normal, replace the master control board:
According to the actual wiring diagram, check whether the
signal line of frequency conversion board, input voltage,
output voltage, compressor terminal and thermal protector are
connected normally.
Detect the output end of the frequency conversion signal of
the master control board through an oscilloscope. If there is no
output signal, replace the master control board:
Under normal conditions, remove the connection triangle of
compressor, connect a new compressor and energize it, if it
starts normally, replace the compressor