Check Of Indoor Electronic Control P.c. Board; Check Of Outdoor Unit - Mitsubishi Electric Mr. Slim MSH09NW Service Manual

Check of indoor electronic control P.C. board

C
The unit doesn't operate with the
remote controller.
Also, the OPERATION INDICATOR
lamp doesn't light up by pressing the
EMERGENCY OPERATION switch.
Check both "parts side"and "pattern
side of indoor electronic control P.C.
board visually.

Check of outdoor unit

D
Compressor and outdoor fan do not operate.(Only indoor fan operates.)
Start
Press EMERGENCY ON/OFF button.
3-minute time delay works.
Test mode operates for 30 minutes.
Check voltage to terminal block of outdoor unit. Is
there AC115V(MSH09),208/230V(MSH12/15/17) to
terminal block between -
L
1
(MSH12/15/17)?
No
Check voltage to terminal block of indoor unit. Is
there DC12V to terminal block between
No
Replace indoor electronic control P.C. board.
Replace the fuse.
Is fuse(F11)blown?
Be sure to check both fuse
and varistor in any case.
Is varistor(NR11)burnt?
Replace varistor.
Yes
(MSH09), -
N L L
1 2
Yes
- ?
1 3
Yes
No
1.Pull out power supply
cord.
2.Measure resistance
between CN201
on electronic con-
1
trol P.C. board and
on the terminal block
with a tester.
No
09NW
Yes
12/15/17NN
Trouble of indoor electronic con-
trol P.C. board.
Is ther resistance?
(Approx.0Ω)
N
Trouble of fuse(F12)
CN201
4 4 1 1
CN201
1 1
4 4
Check the outdoor DEICER P.C. board at first, then check
the outdoor fan motor and the compressor.
Check continuity of indoor and outdoor unit connection.
Yes
No
L
1
N Terminal
block
L L
1
N Terminal N Terminal
block block
49