Service Manual

87
[P12 error]
Does the fan rotate without trouble
when handling the fan with hands?
Remove connectors CN333
and CN334 of indoor unit P.C. board
(MCC-1570).
Is output of
indoor fan motor position
detection signal correct?
3
Are resistance values
between phases at fan motor connector
CN333 motor side of indoor P.C. board
(MCC-1570) correct?
1
Is there no connection error or
disconnection on connectors CN333
and CN334 of indoor unit P.C. board
(MCC-1570)?
Is resistance value of
fan motor connector CN334 motor side
of indoor P.C. board
(MCC-1570) correct?
2
Turn off the power.
1
Are not coil windings between
(Red lead) and
(White lead),
between
(White lead) and
(Black lead),
between
(Black lead) and
(Red lead) opened or shorted?
The resistance should be the resistance value below.
SM40, SM45, SM56, SM80 Approx. 70 to 100
SM110, SM140, SM160 Approx. 27 to 40
Is not grounded between cabinet and
,
,
. It should be 10M or more.
2
Resistance value confirmation of the fan motor position detection circuit
Is not status between
(Yellow lead) and
(Pink lead) opened or shorted?
The resistance should be approx. 5k to 20k.
3
Confirmation of the fan motor position detection signal
Using a voltage tester, measure voltage between CN334
and
on the indoor P.C. board
(MCC-1570) under condition that CN333 and CN334 are mounted and the power supply is turned on.
When rotating the fan slowly with hands, the pin voltage should shake between 0 and 5V.
Between
and
: 5V
CN333
CN334
Replace indoor fan motor.
Check indoor P.C. board
(MCC-1570).
Defect Replace
Correct connection
of connector.
Replace indoor fan motor.
Replace indoor fan motor.
Replace indoor fan motor.
YES
NO
YES
NO
YES
NO
Incorrect
Correct
Incorrect
Correct