Sharp LC-37GE1E (serv.man7) Service Manual ▷ View online
LC-37GE1E
7 – 21
FRC circuit failure
Note: The SD signal (576i 480i) alone passes through the FRC circuit. (The HD signal does not go through.)
Does the image appear with the HD
signal, but not with the SD signal ?
signal, but not with the SD signal ?
Does anything unusual (which or
blackish screen, block noise, for
example) appear on the screen?
blackish screen, block noise, for
example) appear on the screen?
Does the image look unusual with
the power switch turned on?
the power switch turned on?
YES
YES
YES
Is the power supplied to IC3301
(FRC)?
Is there the FRC-IN signal input at pins
(142) and (13) of IC3301?
Check the soldering condition.
(FRC)?
Is there the FRC-IN signal input at pins
(142) and (13) of IC3301?
Check the soldering condition.
Is there the specified RESET-A signal
input at pin (39) of IC3301(FRC)?
(60 ms delay design)
input at pin (39) of IC3301(FRC)?
(60 ms delay design)
Check the connection between pin
(R22) of IC3002 (V-PRO.) and pin
(142) of IC3301 (FRC) as well as
that between pin (N20) of IC3302
and pin(13) of IC3301
(R22) of IC3002 (V-PRO.) and pin
(142) of IC3301 (FRC) as well as
that between pin (N20) of IC3302
and pin(13) of IC3301
YES
NO
Replace IC3301(FRC).
Check "RESET-A " signal pin(34) of
IC1710 (FPGA).
IC1710 (FPGA).
LC-37GE1E
7 – 22
Backlight failure to light up
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
tube (s) with new one (s).
tube (s) with new one (s).
Is the power supplied to CN7501 on
the inverter unit?
the inverter unit?
NO
Check the connection between power
unit and inverter unit.
unit and inverter unit.
YES
Iis the F7501 fuse in the inverter unit
circuit functioning?
circuit functioning?
NO
Replace the blown-out F7501 fuse on
the inverter unit. Turn on the power
again.
If the fuse gets blown out again,
check the short-circuited spot.
the inverter unit. Turn on the power
again.
If the fuse gets blown out again,
check the short-circuited spot.
YES
Check T7501 and T7502 and their
peripheral circuits as well as IC7501
and their peripheral circuits.
peripheral circuits as well as IC7501
and their peripheral circuits.
YES
Is the VCC power supplied to the
control IC (IC7501) on the inverter
unit?
control IC (IC7501) on the inverter
unit?
NO
Check the circuit connected with the
VCC terminal on the inverter control
IC (IC7501).
VCC terminal on the inverter control
IC (IC7501).
YES
Has each control signal come to
CN7502?
(INV-OFL,INV-OSC,INV-STB,INV-
BRT)
CN7502?
(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 IC7501 (INV-CTL) on the
inverter unit.
ted at IC7501 (INV-CTL) on the
inverter unit.
NO
Check the line between CN7502 and
IC7501.
IC7501.
YES
Are the Q7501 and Q7502 transis-
ters at the primary side of T7501
functioning?
ters at the primary side of T7501
functioning?
NO
Check the power line of IC7501,its
peripheral circuits or replace IC7501.
peripheral circuits or replace IC7501.
YES
Is the secondary circuit of T7501
functioning.
functioning.
NO
Replace T7501 or the T75** trans-
former for the fluorescent tubes, or
check their peripheral circuits.
former for the fluorescent tubes, or
check their peripheral circuits.
LC-37GE1E
7 – 23
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.
LC-37GE1E
7 – 23
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.