Read Sharp LC-52XL1E (serv.man3) Service Manual online
LC-46XL1E/RU, LC-52XL1E/RU
4 – 19
Backlight failure to light up (LC-52XL1E/RU)
Do all the fluorescent tubes light up?
NO
Check the individual fluorescent
tubes for light-up failure.
tubes for light-up failure.
YES
Replace any defective fluorescent
tubes with new ones.
tubes with new ones.
YES
Is the power supplied to CN7507B
and CN7507D on the inverter unit?
and CN7507D on the inverter unit?
NO
Check the connection between power
unit and inverter unit.
unit and inverter unit.
YES
Is the fuse (F7501A/B/C/D) in the
inverter unit circuit functioning?
inverter unit circuit functioning?
NO
Replace the blown-out fuse (F7501A/
B/C/D) on the inverter unit. Turn on
the power again.
If the fuse gets blown out again,
check the short-circuited spot.
B/C/D) on the inverter unit. Turn on
the power again.
If the fuse gets blown out again,
check the short-circuited spot.
YES
Check T7501A, T7501B, T7501C and
T7501D and their peripheral circuits
as well as IC7502B and their periph-
eral circuits.
T7501D and their peripheral circuits
as well as IC7502B and their periph-
eral circuits.
YES
Is the VCC power supplied to the
control IC (IC7502B) on the inverter
unit?
control IC (IC7502B) on the inverter
unit?
NO
Check the circuit connected with the
VCC terminal on the inverter control
IC (IC7502B).
VCC terminal on the inverter control
IC (IC7502B).
YES
Has each control signal come to
CN7508B? (INV-OFL, INV-OSC,
INV-STB, INV-BRT)
CN7508B? (INV-OFL, INV-OSC,
INV-STB, INV-BRT)
NO
Have INV-OFL/OSC and the INV-STB
signal come to P1701 (LB) in the
MAIN substrate?
signal come to P1701 (LB) in the
MAIN substrate?
NO
Check pins (19), (17) and (89) of
IC1710 (main PWB).
IC1710 (main PWB).
YES
Is the specified control signal input-
ted at IC7502B (INV-CTL) on the
inverter unit.
ted at IC7502B (INV-CTL) on the
inverter unit.
NO
Check the line between CN7508B
and IC7502B.
and IC7502B.
YES
Are the Q7501B, Q7502B, Q7503B
and Q7504B transistors at the pri-
mary side of T7501B functioning?
and Q7504B transistors at the pri-
mary side of T7501B functioning?
NO
Check the power line of IC7502B, its
peripheral circuits or replace
IC7502B.
peripheral circuits or replace
IC7502B.
YES
Is the secondary circuit of T7501B
functioning.
functioning.
NO
Replace T7501B or the T75*** trans-
former for the fluorescent tubes, or
check their peripheral circuits.
former for the fluorescent tubes, or
check their peripheral circuits.
LCD failure 1
Does a single or several verti-
cal stripes appear on the LCD
screen?
cal stripes appear on the LCD
screen?
Does a single or several hori-
zontal stripes appear on the
LCD screen?
zontal stripes appear on the
LCD screen?
Do luminescent or black dots
appear on the screen?
appear on the screen?
Is the on-screen image rip-
pling or distorted?
pling or distorted?
Replace the LCD panel.
LCD failure 2
The backlight func-
tions. Does not the
image come out in the
LCD screen (screen
black)?
tions. Does not the
image come out in the
LCD screen (screen
black)?
Does the entire LCD
screen look whitish all
over?
screen look whitish all
over?
Does the QS drive func-
tion?
tion?
Are the data bit drop-
out?
(No solution even when
turning on and off the QS
drive)
out?
(No solution even when
turning on and off the QS
drive)
Is the gamma correc-
tion as specified?
tion as specified?
Replace the LCD control unit.
Click on the first or last page to see other LC-52XL1E (serv.man3) service manuals if exist.