Midea MSMBB-12CRDN1-MP0W Service Manual page 35

Remark:
Use a multimeter to test the DC voltage
between L2 port and S port of outdoor
unit. The red pin of multimeter connects
with L2 port while the black pin is for S
port.
When AC is normal running, the voltage
will move alternately between -50V to
50V.
If the outdoor unit has malfunction, the
voltage will move alternately with positive
value.
While if the indoor unit has malfunction,
the voltage will be a certain value.
Remark:
Use a multimeter to test the resistance
of the reactor which does not connect
with capacitor.
The normal value should be around zero
ohm. Otherwise, the reactor must have
malfunction and need to be replaced.
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