– 87 –
11-9. How to Check Simply the Main Parts
11-9-1. How to Check the P.C. Board (Indoor Unit)
(1) Operating precautions
1) When removing the front panel or the P.C. board, be sure to shut off the power supply breaker.
2) When removing the P.C. board, hold the edge of the P.C. board and do not apply force to the parts.
3) When connecting or disconnecting the connectors on the P.C. board, hold the whole housing. Do not
pull at the lead wire.
(2) Inspection procedures
1) When a P.C. board is judged to be defective, check for disconnection, burning, or discoloration of the
copper foil pattern or this P.C. board.
2) The P.C. board consists of the following 2 parts
a. Main P.C. board part :
DC power supply circuit (5V, 12V, 35V), Indoor fan motor control circuit, CPU and peripheral circuits,
buzzer, and Driving circuit of top/ bottom louver.
b. Indication unit of infrared ray receiving infrared ray receiving circuit, LED :
To check defect of the P.C. board, follow the procedure described below.
NG
NG
NG
OK
OK
OK
Check
winding of
compressor.
Check
fan motor
position
detect
signal.
Replace
com-
pressor.
C
B
A
Replace
outdoor
fan
motor.
Replace control
board assembly.
Replace
control board.
Replace
compressor.
Check
compressor
winding
resistance.
Diagnosis/Process flowchart
Item
Check
Opera-
tion
Check
Contents
Check winding resistance
between phases of compres-
sor, and resistance between
outdoor frames by using a
tester.
• Is not grounded.
• Is not short-circuited
between windings.
• Winding is not opened.
Remove connector CN300 of
the outdoor fan motor, turn on
the power breaker, and
perform the operation.
(Stops though activation is
prompted.)
Check operation within 2
minutes 20 seconds after
activation stopped.
<Output check of fan motor
position detect signal>
While connecting connector
5P (CN301) for position
detection, using a tester,
measure voltage between
–
.
Between
–
: 5V
Summary
→
OK if 10M
Ω
or more
→
OK if 0.2
Ω
(under 20°C)
(Check by a digital tester.)
a) One or two of three
voltages should be 5V,
and others should be 0V.
(When all are 0V or 5V, it
is not accepted.)
b) When rotating the fan
slowly with hands, the
voltage between pins
should move from 0V to 5V.
(Check it with an analog
tester.)
Summary of Contents for RAS-3M18SACV-E
Page 21: ... 21 4 2 Outdoor Unit RAS 3M18SAV E RAS 3M18SACV E ...
Page 110: ... 110 MCC 1438 ...
Page 111: ... 111 MCC 818 ...
