Brother DP-525CJ Service Manual page 74

REPAIR
SERVICE MANUAL
Points to Check
Is the correct voltage (about 25V-
36V) applied to the LCD on pin 11 of
connector CN8 of the Main PCB?
(640 400 LCD)
Is oscillator XT1 operating correctly?
(Use an oscilloscope to check)
Do the output pulses from MRD of
#8 change?
9
Problem: LCD displays operates, but data displayed is incorrect (does not match input).
Points to Check
Is solder present at the correct
Country Specification Change-Over
Solder Point?
Is there an output wave form at each
pin in the connector CN7 or CN8
Is there faulty soldering the LCD
module?
Do the CBIC (#8) MA0-MA14 pulses
change sequentially
Do video RAM (#6) MD0-M7 change
in response to the MA0-MA14
pulses?
10
Problem: Word processor prints when no paper is set, or will not print when paper is set (Paper
End Sensor malfunction)
Points to Check
Is the PE(paper end) switch properly
installed?
Is the PE switch lever stuck?
Is the PE switch damaged?
Does pin 1 of CN14 go LOW when
paper is not set and HIGH when
Paper is set?
Does the switch function abnormally
even though the above signals are
normal?
Probable Cause
Incorrect power supply
voltage to LCD module
Defective XT1 or #7
Defective #8
Probable Cause
Incorrect or faulty
solder point for
specified country
(language)
Defective #8 or solder
bridge
Defective #8
Defective #6
Probable Cause
Incorrect installation
Incorrect installation
Harness wire break or
defective PE switch
Defective #8
3-11
Troubleshooting
Corrective Action
Replace the Main
PCB.
Corrective Action
Verify and correct
solder point.
Replace the Main
PCB.
Replace the LCD
module.
Corrective Action
Reinstall.
Reinstall.
Replace the PE
switch.
Replace the harness
or the PE switch.
Replace the Main
PCB.
Repair
Replace XT1,
#7.
Replace #8.
Repair
Replace #8.
Replace #8.
Replace #6.
Repair
Replace #8.