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68
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'14 • KX-SM-204
2.2 Explanation of troubleshooting
(a) Checking DC15V on the control PCB (Step to check if the inverter PCB fails or not)
Use this to diagnose E41, E42, E45 and E48.
(b) Inspection of short-circuit on the power transistor module terminals
Disconnect the wiring of compressor and check for short-circuit with a tester.
Inspect between terminals of: P-U, P-V, P-W, N-U, N-V, N-W and P-N
It will be easier to contact the tester at the following place at each terminal.
P: P terminal of power transistor
N: N terminal of power transistor
U: End of red harness to compressor
V: End of white harness to compressor
W: End of blue harness to compressor
Power OFF (Power supply circuit breaker OFF)
Fan motor check
Even if DC15V is detected, affection by fan motor anomaly is
suspected. Implement following check.
*Be sure to check both fan motor 1 and 2
*After completion of checking both fan motor 1 and 2,
replace the anomalous fan motor.
Turn the power ON (power circuit breaker ON)
and start operation with the test run SW.
Check between #1 and #2 of CNI1 on the control
PCB to see if DC15V is detected.
Be sure to wait for 3 minutes after turning the
power circuit breaker off.
Disconnect the fan motor wires.
(Both the power cable and control wires)
Turn the power circuit breaker OFF
Wait 3 minutes
Check whether DC15V between
①
-
②
of CNI1
on the control PCB is detected.
Check
E41, 42, 45, 48
Connect the wires of fan motor 1 or 2
Power ON
Test run switch ON
If DC15V is detected, primary check is completed.
Return to
①
and check fan motor 2
(Between
①
-
③
of CNI3).
If no problem on both fan motor 1 and 2, go to further
diagnosis of E41, E42, E45, E48 sequentially.
If DC15V is not detected, the connected fan motor
has anomaly.
Turn the power OFF and disconnect the wires.
If the check of fan motor 2 is not completed, return to
①
and check fan motor 2 (Between
①
-
③
of CNI3).
Since, unless DC15V is detected, faulty inverter PCB is suspected,
check CNI1 at the control PCB side, the connector connection of
CNI2 at the inverter side and breakage of communication wires.
If everything is all right, replace the inverter PCB.
①
②
③
Terminal (+)
P
N
P
P
P
N
N
N
U
V
W
U
V
W
Terminal (--)
N
P
U
V
W
U
V
W
P
P
P
N
N
N
Normal value (
Ω
)
About 1M
About 300-400
0
About 1.2M
About 1.3M
0
Several 10 M
Several 10 M
Several 10 M
Several 100k
Several 100k
Several M
Note (1) When a measured value is 0 – a few k
Ω
, the element may be broken. Replace the power transistor part.
