SiBE12-908
Check
Service Diagnosis
167
3. Diagnose method (Diagnose can be made according to 6 LEDs lighting status as
follows:)
(1) When all LEDs are lit uniformly,
→
Compressor malfunction (to be replaced)
(2) When some of LEDs are not lit (LEDs are not lit or go off, etc.):
Check the individual power transistor. (Refer to check No.15)
∗
When the power transistor and control PCB are integrated :
→
Replace the control PCB.
∗
When the power transistor can be checked individually :
↓
Check the resistance value. (Refer to check No.15)
If NG :
→
The power transistor may have a failure. (Replace the power transistor).
If the power transistor is normal, check if there is any solder cracking on the filter PCB.
∗
If any solder cracking is found:
→
Replace the filter PCB (or repair the soldered section).
∗
If the filter PCB is normal:
→
Replace the control PCB.
Caution
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When the output frequency is low, the LED flashes slowly. As the frequency increases, the
LED flashes quickly. (It looks like the LED is lit)
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If the operation is carried out with no load (the condition of the compressor is disconnected),
some of units may stop operation with “CT system error” (due to no electric current) or
“startup failure” (because the compressor does not turn). In this case, check if the LED is
flashing during “operation” to “malfunction stop”. (Refer to the service manual of each air
conditioner for checking whether the alarm LEDs for CT system, startup failure, etc. are
provided or not.)
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On completion of diagnose by this checker, be sure to re-crimp the faston terminal for
resetting the system.
(Otherwise, the terminal may be burned due to loosening.)
3.9
Power Transistor Check
Check No.15
Do not touch the live parts within 10 min. after the breaker is turned off.
Even after that, when you touch the parts, check to see that supply voltage of the power
transistor is less than 50 V with a tester.
Measure resistance at connector terminal on PCB or at the relay connector.
Direction of crimp
This size is shortened
by “crimp”.
Faston terminal
(R5161)
(–) terminal of a tester
Power transistor
(+)
UVW
Power transistor
(–)
UVW
(+) terminal of a tester
UVW
Power transistor
(+)
UVW
Power transistor
(–)
Resistance in OK
several k
Ω
~several M
Ω
Resistance in NG
0 or
∞
