Daewoo FRS-U20DD. Service Manual page 46

5) Frequency mode connection & Check point
The main-PCB is connected to the Inverter through the Control Input Connection, using the Control Input Cable.
Frequency signal to the IN pin and the 0V to the GND pin (see below Figure)
- Inverter AC Input & Input & Output Signal
Main-PCB
b. Input Signal
Measure the input signal frequency
with Oscilloscope (Hz).
- Compressor Motor Winding
a. AC Input
Measure the AC input voltage with multi tester
46
INVERTER
c. Output Signal
Measure the output signal frequency
with Oscilloscope (Hz).
Measure winding for open circuit between
all pair of pins on the hermetic terminal.
1)
R1 = R2 = R3
- Compressor Motor Winding is OK.
2) are not same
R1, R2, R3
- Compressor Motor Winding is OPEN.