Daikin REYQ8-48PY1B, Service Manual

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Method of Checking the Inverter’s Power Transistors and Diode Modules SiBE37-701_B
453 Appendix
9. Method of Checking the Inverter’s Power
Transistors and Diode Modules
9.1 Method of Checking the Inverter’s Power Transistors
and Diode Modules
Checking failures in power semiconductors mounted on inverter PCB
Check the power semiconductors mounted on the inverter PCB by the use of a multiple tester.
<Items to be prepared>
h
Multiple tester : Prepare the analog type of multiple tester.
For the digital type of multiple tester, those with diode check function are
available for the checking.
<Test points>
h
Turn OFF the power supply. Then, after a lapse of 10 minutes or more, make measurement
of resistance.
<Preparation>
h
To make measurement, disconnect all connectors and terminals.
Inverter PCB
Electronic circuit
„
According to the checking aforementioned, it is probed that the malfunction results from the
faulty inverter. The following section describes supposed causes of the faulty inverter.
h
Faulty compressor (ground leakage)
h
Faulty fan motor (ground leakage)
h
Entry of conductive foreign particles
h
Abnormal voltage (e.g. overvoltage, surge (thunder), or unbalanced voltage)
In order to replace the faulty inverter, be sure to check for the points aforementioned.
J1
J2
J3
P1 P3
N3 U V W
X10A K2
L1
L2
L3
J1
J2
J3
DM
P1 P2 P3
IGBT
N3
U V W
X11A
(V2895)