9-7. Troubleshooting for P.C. board
9-7-1. How to check indoor P.C. board
<Cautions for handling P.C. board>
(1) When removing the front panel and the P.C. board,
be sure to turn off the power supply.
(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 housing. Do not pull at
lead wires.
– 53 −
FILE NO. SVM-08032
1 Turn off the power supply and
remove the P.C. board assembly
from electric parts base. Remove
the connecting cables from the
terminal block.
2 Remove the connector of the motor
and turn on the power supply. If
OPERATION lamp blinks (once per
second), it is not neccessary to
check steps (1 to 3) in the right
next column.
3
Press [ ] button once
to start the unit. (Do not set the
mode to Fan Only or On-Timer
operation).
4 Shorten the line of the restart delay
timer and start unit.
<Inspection procedure>
(1) If the P.C. board is defective , check for disconnec-
tion, burn or discoloration of the copper foil pattern
of the P.C. board.
(2) The P.C. board consists of the following 2 parts:
a. Main P.C. board parts.
Power relay, indoor fan motor drive circuit and
control circuit, C.P.U. and peripheral circuits, buzzer
drive circuit and buzzer.
b. Infrared rays parts:
Infrared rays receiving circuit
Check the defects of the P.C. board with Table 9-7-1.
Table 9-7-1 Inspection procedure
No. Procedure Check points Causes
Impluse voltage was applied or the
indoor fan motor short-circuited.
1. The terminal block or the
crossover cable is connected
wrongly.
2. The capacitor (C25 and C26 )
line filter (L01), resistor (R64), or
the diode (DB01) is defective.
3. C32 and T01 are defective.
4. IC02, C35 or T01 are defective.
1. The wire of the relay coil (RY02)
comes down or the relay drive
(Q02) is defective.
2. CN27 or RY02 is connected
wrongly.
The lamps are defective or the
housing assembly (CN13) is
defective.
Check whether or not the fuse (F01)
is blown.
Check power supply voltage;
1. Between pin 1 - 2 of CN33
(220 − 240 V AC) : Except
2. Between + and −
(DC310 − 340 V)
3. Between 12 V and GND
4. Between 5 V and GND
1. Between collector of Q02 and
GND (for relay coil (DC12 V))
2. Between
2
and 3 of terminal
block for connecting cable
Check whether or not all lamps
(OPERATION, Auto restart,
TIMER PAP, FILTER and Hi-power)
are indicated for 3 seconds and they
return to normal 3 seconds later.
RAS-18SKPX, RAS-18SKPX-V, RAS-18SKP-E
of CN27
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