Daikin AT12BV1LS Pocket Manual page 164

Si10-417
5.4.11 Capacitor Voltage Check
Check
No.12
5.4.12 Power Transistor Check
Check
No.13
Service Diagnosis
Checking the capacitor voltage
With the circuit breaker still on, measure the voltage at
the power transistor (+) and (-) terminals. Set the
multi-tester to DC and VOLTAGE RANGE before
measurement. Be careful never to touch any live
parts.
* Since capacitor (+) and (-) are connected to power
transistor (+) and (-), capacitor voltage can be
measured at the power transistor (+) and (-) terminals.
Checking the power transistor
Never touch any live parts for at least 10 minutes after
turning off the circuit breaker.
If you cannot avoid to touch a live part, make sure that
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.
Tester's Power
negative transistor
terminal
Tester's
positive UVW
terminal
Normal
resistance
Abnormal
resistance
UVW
(+)
Power
transistor
(+)
Several kΩ to several MΩ
Troubleshooting
Power
transistor
(–)
UVW
0 or ∞
UVW
Power
transistor
(–)
163