Panasonic CS-MRE7PKE, Service Manual

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17.4.25 F99 (Output Over Current Detection)
Malfunction Decision Conditions
During operation of cooling and heating, when an output over-current (DC peak current value at IPM Prevention
Control) is detected by checking the current that flows in the inverter DC peak sensing circuitry.
Malfunction Caused
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Faulty outdoor unit PCB
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Faulty compressor
Troubleshooting
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Checking the power transistor
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Never touch any live parts for at least 10 minutes after turning off the circuit breaker.
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If unavoidable necessary to touch a live part, make sure the power transistor’s supply voltage is below 50V using
the tester.
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For the UVW, make measurement at the Faston terminal on the board of the relay connector.
Tester’s negative terminal Power transistor (+) UVW Power transistor (-) UVW
Tester’s positive terminal UVW Power transistor (+) UVW Power transistor (-)
Normal resistance Several k Ω to several M Ω
Abnormal resistance 0 or ∞