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CHECK 1
Symptom
No operation
Remote control is not received.
Preliminary checks
∗ Is the power cord plugged in?
∗ Is power present at plug socket?
∗ Is power turned off?
(1) Power connection check
∗ Is power received at main PC board terminal
K101/W101? (220 or 240V AC)
∗ Is fuse (3A) blown?
(2) Power transformer check
∗ Are CN103 [CN101] and CN102 [CN103] inserted firmly?
∗ Is 15 to 20V AC output at CN102 [CN103]?
(3) Power supply circuit check
q 12V line
0V
D101, Q101 faulty
D104 [D102], C104 [CN106] shorted
R101 open
w 5V line
0V
D5 open, IC102 faulty
C9, C10 shorted.
Other parts shorted.
(4) Power interrupt signal faulty
R3, R5 open, C12 shorted,
IC3-1 faulty.
(5) Reset IC faulty
IC4 faulty.
(6) Microcomputer oscillator faulty
Is oscillator waveform (8.0 MHz) output at
microcomputer pins 30 and 31?
If oscillation waveform is not output, X1 or
microcomputer is faulty.
(7) Microcomputer faulty
CHECK 2
Preliminary checks
∗ If air conditioner operates when remote control battery
is changed, there are no problems. (Battery life is six
months to one year.)
∗ When receiving part of remote control unit is exposed
to direct sunlight, the remote control receiver may not
be received.
∗ When infrared signal between remote control unit and
receiver is blocked, the remote control is not received.
(1) Remote control unit check
If signal tone is heard when a transistor radio is
tuned to an unused frequency in medium wave band
and remote control button is pressed within 5cm of
radio, remote control unit is normal.
(2) When the remote control unit is normal
Is CN9 disconnected?
Receiver at air conditioner indicator PC board is
faulty, or main PC board is faulty.
CHECK 3
Symptom
Erroneous operation (Runaway)
Preliminary checks
∗ Set wall outlet to OFF and wait at least 30 seconds.
Then, set wall outlet to ON again. If remote control
unit is received normally, there is no trouble.
(1) Reset circuit faulty
IC4 faulty, C14 shorted
NOTE : [ ] Ref. No. of 7,000 BTU/H Model
CHECK 4
Symptom
Display does not light correctly.
Preliminary checks
∗ Is display PC board connector CN9 inserted
firmly?
∗ Is display unit cable open?
(1) LED driver faulty
IC6 faulty, R16 to R18 open. If all of above are
normal, display unit is faulty.
CHECK 5
Symptom
Room temperature cannot be controlled.
(Compressor does not run or does not stop.)
Preliminary checks
∗ Is TEST-MANUAL AUTO switch in TEST position?
TEST indication check
ON
Operation
Lamp
OFF
ON
Timer
Lamp
OFF
(Timer lamp operates similarly)
∗ Is room temperature or thermistor connector CN12
inserted firmly?
∗ Is set temperature correct?
(1) Thermistor faulty
Room temperature thermistor resistance values are
shown on page 17.
When there is a large error, thermistor is faulty.
(2) A/D input circuit faulty
R32 open or shorted, R30 open, C26 and C32
shorted. If all of above are normal, advance to
CHECK 6.
CHECK 6
Symptom
Room temperature cannot be controlled.
Preliminary checks
∗ Is each Faston terminal CN16-CN107 of power relay
inserted firmly?
∗ Is indoor unit and outdoor unit connection wiring open
or loose?
(1) IC5 [IC6] faulty
IC5-5 [IC6-4] output port shorted.
K101 Power relay faulty
CHECK 7
Symptom
Room fan does not run.
Preliminary checks
∗ At dehumidification operation, room fan is stopped
while compressor is stopped.
∗ Turn fan once or twice by hand.
If fan does not turn easily, fan motor is faulty.
(1) Fan motor faulty
Fan motor winding open (check between all
windings)
(2) Fan motor capacitor faulty, C101 [C105] open.
(3) Relay drive circuit faulty
IC5 [IC6] faulty
IC5-2 [IC6-7] output port shorted
SSR101 faulty, L101 open
– 16 –
1.0 sec
1.0 sec
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