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62
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'19 • PAC-SM-334
(6) Power transistor module (Including the driver PCB) inspection procedure
Compressor operation
Replace the outdoor
unit inverter PCB
Normal
YES
YES
YES
NO
NO
NO
Is the power
transistor module
cracked or burnt?
Is there a
short circuit between the
power transistor module
terminals?
∗
(1)
If there is a 10% or greater difference
in the current in different phases.
(except during acceleration or deceleration)
Is there any difference in
the compressor current
between phases?
*(1) Power transistor module terminal short circuit check procedure
Disconnect the compressor wiring, then conduct a short circuit check.
P-U, P-V, P-W
N-U, N-V, N-W
Check between the P-N terminals.
Bring the tester probes in contact with the following
places on each te rminal.
P: Power transistor P terminal,
N: Power transistor N terminal,
U: End of red harness to compressor
V: End of white harness to compressor
W: End of black or blue harness to compressor
Check for a power transistor short-circuit.
• When you do not have a diagnostic checker for judging if the inverter
is defective, measure between the terminals of the power transistor
parts, judge whether the power transistor is defective or not.
• Disconnect the compressor, then measure with the control
incorporated.
Model FDC90, 100VNP-W
Tester
Normal values (
W
)
Diode mode (V)
Terminal
(+)
Terminal
(-)
P
N
A few of M
W
(Not short)
—
N
P
P
U
P
V
P
W
N
U
Approx. 0.4V
N
V
N
W
U
P
V
P
W
P
U
N
—
V
N
W
N
If the measured values range from 0 - several k
W
, there is a possibility that the
elements are damaged, so replace the power transistor parts.
