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 100Ω
SM110, SM140, SM160 → Approx. 27 to 40Ω
• Is not grounded between cabinet and

,

,

. → It should be 10MΩ 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 20kΩ.
∗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