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Chapter vi troubleshooting, Troubleshooting of malfunctions – Brother HL-1260 User Manual

Page 153

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VI

- 1

CHAPTER

VI

TROUBLESHOOTING

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 supplied

M-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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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.