I-7
Black and blurred horizontal stripes
Possible cause
Step
Check
Result
Remedy
Scratch on the
drum
1
Are the horizontal stripes at 94mm
intervals?
Yes
Replace the drum
unit.
Toner stuck on
the develop
roller
2
Are the horizontal stripes at 17mm
intervals?
Yes
Print several sheets
and see what
happens.
The problem will
disappear after a
while.
Scratch on the
fixing roller
3
Are the horizontal streaks at 50 mm
intervals?
Yes
Replace the fixing
unit.
I-8
Dropout
Possible cause
Step
Check
Result
Remedy
Transfer failure
1
Is the transfer roller soiled? Is it
scratched?
Yes
Replace the drum
unit.
High-voltage
power supply
failure
2
Open the top cover and measure
the voltage at the transfer electrode
plate at the right side while printing
with the interlocks defeated.
Is the voltage correct?
Yes
Check the harness
connection between
the high-voltage
power supply and
the panel sensor
PCB. If the
connection is normal,
replace the high-
voltage power supply
PCB.
Содержание HL-720
Страница 1: ...SERVICE MANUAL MODEL HL 720 730 730Plus R LASER PRINTER ...
Страница 36: ...II 19 1 3 10 Engine I O HL 720 Fig 2 21 shows the engine interface circuit Fig 2 21 ...
Страница 37: ...II 20 HL 730 730Plus Fig 2 22 shows the engine interface circuit Fig 2 22 ...
Страница 61: ... Fig 3 18 2 4 1 1 1 ...
Страница 92: ...SERVICE MANUAL MODEL HL 760 R LASER PRINTER ...
Страница 109: ...II 8 1 3 4 DRAM Two 4M bit DRAMs x 16bits are used as the RAM Fig 2 6 ...
Страница 113: ...II 12 1 3 10 Engine I O Fig 2 12 shows the engine interface circuit Fig 2 12 ...
Страница 114: ...II 13 1 3 11 Paper Feed Motor Drive Circuit Fig 2 13 ...
Страница 133: ...Appendix 2 Main PCB Circuit Diagram 1 3 CODE UK3227000 B48K272CIR 1 3 NAME ...
Страница 134: ...Appendix 3 Main PCB Circuit Diagram 2 3 CODE UK3227000 B48K272CIR 2 3 NAME ...
Страница 135: ...CODE UK3227000 B48K272CIR 3 3 NAME Appendix 4 Main PCB Circuit Diagram 3 3 ...