Troubleshooting For P.c. Board - Toshiba RAS-24NKHD-E4 Service Manual

9-9. Troubleshooting for P.C. board

9-9-1. 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.
No. Procedure
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 detective, 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 9-8-1.
Table 9-9-1 Inspection procedure
Check points
Check whenther or not the fuse (F01)
is blown.
Check power supply voltage;
1. Between CN30 and CN31
(220 − 240 V AC) : Except
2. Between + and − of C63
(DC310 − 340 V)
3. Between 12 V and GND
4. Between 5 V and GND
Check power supply voltage;
<Heat pump model>
1. Between CN31 and CN23
(DC15 − 60 V)
<Cooling only model>
1. Between connector of Q24 and
GND (for relay coil (DC12 V))
2. Between 1 and 2 of terminal
block for connecting cable
Check whether or not all lamps
(OPERATION, TIMER, PRE.-DEF.
(or FAN ONLY), FILTER. and Hi Power)
are indicated for 3 seconds and they
return to normal 3 seconds later.
– 74−
FILE NO. SVM-05016
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 (R319), or
the diode (DB01) is defective.
3. C65, C66 and M01 are defective.
4. IC04, C05, C06 and C07 are
defective.
<Heat pump model>
IC32 and IC33 are defectice.
<Cooling only model>
1. The wire of the relay coil (RY04)
comes down or the relay drive
(Q24) is defective.
2. CN27 or RY04 is connected
wrongly.
The lamps are defective or the
housing assembly (CN13) is
defective.