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.
–
48
−
FILE NO. SVM-10035
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 (C01 and C02 )
line filter (L01), resistor (R09), or
the diode (DB01) is defective.
3. C27, T01 and IC01 are defective.
4. IC10, C30, C11 or T01 are
defective.
IC03 or IC04 are defectice.
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 CN30 and CN31
(AC 220-240V) : Except
2. B and
−
of C03
(DC310
−
340 V)
3. Between 12 V and GND
4. Between 5 V and GND
Check power supply voltage;
1. Between CN31 and CN23
Check whether or not all lamps
(OPERATION, PRE.DEF, TIMER
and FILTER) are indicated for
3 seconds and they return to mormal
3 seconds later.
(AC70 ~ 100V)
.
.
.C. board are defective.
er to Table 9-7-2.)
.
.C. board is defective.
.
.
5 Press [ ] button once
to start the unit.
•
Shorten the time of the restart
delay timer.
•
Set the operation mode to COOL.
•
Set the fan speed level to AUTO.
•
Set the preset temperature must
lower than the room temperature.
(The unit (compressor) operates
continuously in the above
condition.)
1. The temperature of the indoor
heat exchanger is extremely low.
2. The connection of the heat
exchanger sensor is loose.
(The connector is disconnected.)
(CN01)
3. The heat exchanger sensor and
the P.C. board are defective.
(Refer to Table 9-8-2.)
4. The main P.C. board is defective.
1. Check whether or not the
compressor operates.
2. Check whether or not the
OPERATION lamp blinks.
