Capacitor Voltage Check; Power Transistor Check - Daikin ATXS35EV1B7 Service Manual

SiBE04-824

5.1.10 Capacitor Voltage Check

Check No.12 Before this checking, be sure to check the main circuit for short-circuit.

5.1.11 Power Transistor Check

Check No.13
25/35 class
Note: Check to make sure that the voltage between the terminal of Power transistor (+) and (-) is
approx. 0 volt before checking power transistor.
< Measuring method >
Disconnect the compressor harness connector from the outdoor unit PCB. To disengage the
connector, press the protrusion on the connector.
Then, follow the procedure below to measure resistance between power transistor (+) and (-)
and the U, V and W terminals of the compressor connector with a multi-tester. Evaluate the
measurement results for a pass/fail judgment.
<Power transistor check>
Negative (-) terminal of
tester (positive terminal
(+) for digital tester)
Positive (+) terminal of
tester (negative terminal
(-) for digital tester)
Normal resistance
Unacceptable resistance
50 class
Service Diagnosis
Checking the capacitor voltage
With the circuit breaker still on, measure the voltage according to the drawing of the model in
question. Be careful never to touch any live parts.
Multimeter
(DC voltage range)
Compressor lead wire
Fan motor lead wire
Power transistor
Checking the power transistor
Never touch any live parts for at least 10 minutes after turning off the circuit breaker.
If unavoidably necessary to touch a live part, make sure the power transistor's supply
voltage is below 50 V using the tester.
For the UVW, make measurements at the Faston terminal on the board or the relay
connector.
Reactor lead wire
Electronic expansion valve
lead wire
UVW
(+)
UVW Power transistor
(+)
Several kΩ to several MΩ (∗)
Short (0 Ω) or open
OL lead wire
Thermistor lead wire
Reversing solenoid
valve lead wire
(Heat pump type only)
(R5222)
Power transistor UVW
(-)
UVW Power transistor
(-)
Check
133