Mitsubishi SRK18CL Technical Manual & Parts List page 32

(8) Checking the indoor electrical equipment
(a) Indoor PCB check procedure
Is there voltage between terminal
blocks ① and ② ? (AC 220/230/240V)
YES
Is the fuse burnt out? (3.15 A)
YES
Force cooling operation
Is there voltage between
terminal blocks ② and ③ ?
(AC 220/230/240V)
YES
Indoor electrical components
are normal.
(b) Indoor unit fan motor check procedure
1) Indoor PCB output check
DC several V
(4~6 V)
CNU
2) Fan motor resistance check
Measuring point
① − ③
−
④ − ③
NO
Inspect power source
for outdoor unit.
NO
Replace fuse.
NO
Replace indoor PCB.
GND
DC15V
⑥ ⑤ ④ ③
⑥ ⑤ ④ ③
FM
I
Resistance when normal
−
k
(–)
DC 308~336V
Indoor PCB
② ①
② ①
0
- -
'09•SRK-SM-087D
'12 • SRK-T-125
① ④ ⑤
Measuring Resistance when
point normal
① − ③
④ − ③
⑤ − ③
⑥ − ③