Panasonic WH-UD30BE5-1 Service Manual page 51

To determine if outdoor unit PCB or indoor unit PCB is faulty:
1. Start with outdoor terminal.
2. Remove terminal 3 wire.
3. Measure with a multimeter (voltage in DC range).
4. If it is never constant, and outdoor PCB is good fluctuating in between 20-70Vdc, outdoor PCB is in good condition.
16.5.8. Unspecified Voltage between Indoor and Outdoor (H95)
Malfunction Decision Conditions:
The supply power is detected for its requirement by the indoor/outdoor transmission.
Malfunction Caused:
1. Wrong models interconnected.
2. Wrong indoor unit or outdoor unit PCB used.
3. Faulty indoor unit or outdoor unit PCB.
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