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VI - 11
Malfunction of control panel LED lamps.M-3
Possible cause Step Check Result Remedy
LED lamps Dose the voltage of the following signals stay
0V while the "04 SELF TEST " is displayed
after switching the power on and stay 5V for
about 0.5 seconds after the message goes off?
(Do the LED lamps turn on and off in response
to the signal levels of 0V and 5V?)
1
Control panel
PCB
Switch flat cable
Main PCB Signal
LED1(ON LINE)
LED2(READY)
LED3(DATA)
LED4(ALARM)
Main PCB
P1-13
P1-7
P1-1
P1-6
Panel PCB
P1-9
P1-15
P1-21
P1-16
Yes
No
Replace the control panel
unit.
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Replace the main PCB assy
or the switch flat cable.
4. TROUBLESHOOTING OF MALFUNCTIONS
Is the voltage of P3-8 in the low-voltage power
supply PCB connector 0V?
Possible cause Step Check Result Remedy
PCBs 1 Does any PCB have the short circuit between
+24V and 0V,+5V and 0V or +24V and +5V?
Yes Replace the PCB having the
short circuit.
Low-voltage
power supply
PCB
Main PCB
LV harness
DC fan motor
2
Yes
Replace the low-voltage power
supply PCB assy.
No
Replace the main PCB assy,
the LV harness or the DC fan
motor.
No DC power suppliedM-1
Possible cause Step Check Result Remedy
LCD module 1 Yes
No
Replace the main PCB assy,
the switch flat cable or the
control panel unit.
Malfunction of LCD display on the control panel.M-2
Dose the voltage of the following signals
vary to 5V or 0V when the LCD displays are
changed through switch operations?
(Check following signals using the digital
memory scope with the trigger function for
this check)
Control panel
PCB
Switch flat cable
Main PCB Signal
PAD4
PAD5
PAD6
PAD7
LCDRS
LCDE
Main PCB
P1-9
P1-5
P1-11
P1-4
P1-3
P1-2
Panel PCB
P1-13
P1-17
P1-11
P1-18
P1-19
P1-20
P2-4
P2-3
P2-2
P2-1
P2-7
P2-5
Replace the control panel
unit.
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LCD
7
8
9
10
4
6
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