Read Sharp LL-T1512W (serv.man5) Service Manual online
LL-T1512W
4 – 1
CHAPTER 4. TROUBLESHOOTING
No power supply
Does LED turns on in green
when power switch is turned
on?
when power switch is turned
on?
No
No
No
No
No
No
LED turns on in red?
Yes
Yes
Yes
Yes
Yes
Yes
Yes
* Check LED for breakage.
* Check cable for disconnection.
* Check cable for disconnection.
Replace any unit (main PWB, SW PWB, cable)
which shows any defect, with a new one.
which shows any defect, with a new one.
1) PC is turned off?
2) RGB cable is disconnected?
3) Synchronizing signal is output from RGB
2) RGB cable is disconnected?
3) Synchronizing signal is output from RGB
cable?
Check whether the unit is in power save
mode (synchronizing signal is not input.).
mode (synchronizing signal is not input.).
Synchronizing signal is input to main PWB?
Replace RGB cable
with a new one.
with a new one.
LED turns on in orange?
Check power input system.
1) AC adapter
* Normal?
* Connected properly?
2) Blown out fuse (F1, F2) ?
3) Each signal of 5V, D3, 3V, PVDD,
* Normal?
* Connected properly?
2) Blown out fuse (F1, F2) ?
3) Each signal of 5V, D3, 3V, PVDD,
AVDD1.8V is output ?
4) LED
* Check LED for breakage.
* Check the path between CN10 and
* Check LED for breakage.
* Check the path between CN10 and
IC22.
* Check the cable for disconnection.
Replace any defective unit.
[ 1) Adapter, 2) A Main PWB, 3) Switch
PWB, ] with a new one.
[ 1) Adapter, 2) A Main PWB, 3) Switch
PWB, ] with a new one.
Backlight turns ON?
Check for RGB cable input
signal.
signal.
Replace RGB cable.
Normal
Normal
Normal
Defective
Defective
* Check inverter block of main PWB.
Note: Use caution when checking output
Note: Use caution when checking output
side because it has a high voltage.
Replace LCD module lamp with
a new one.
a new one.
Replace main PWB
unit with a new one.
unit with a new one.
A
Check each signal of
BL_ON,+12V,BRI(150Hz,
Duty 15~65%)
BL_ON,+12V,BRI(150Hz,
Duty 15~65%)
LL-T1512W
4 – 2
A
Screen does not operate normally.
Check RGB cable.
Check DVI cable.
Defective
Replace RGB cable or
DVI cable with a new
one.
DVI cable with a new
one.
Check screen condition by changing display modes.
Reset the all adjustment to check if screen condition changes.
(Press and hold MENU and SELECT buttons while turning on power switch.)
(Press and hold MENU and SELECT buttons while turning on power switch.)
Screen stays in black.
Screen stays in white.
Screen jitters or on-screen
characters flicker.
characters flicker.
Abnormal color
Check the following signals
1) Check if module control signal (IC15) is output.
2) Check if gate voltage (5VLCD) is output
normally.
3) Check if Source voltage (3.3VLCD) is output
normally.
Yes
No
Yes
No
Yes
No
CLOCK and PHASE
can be adjusted?
can be adjusted?
Does abnormal area move on
screen when BLACK LEVEL or
CONT is changed after H-POS
or V-POS is set?
screen when BLACK LEVEL or
CONT is changed after H-POS
or V-POS is set?
Switch PWB defective
Main PWB defective.
LCD panel defective.
Normal
3.3 V output is generated?
(USB PWB IC1 3pin)
(USB PWB IC1 3pin)
Check regulator
(USB PWB IC1)
and its peripheral circuits.
(USB PWB IC1)
and its peripheral circuits.
No
Yes
Clock is generated
(4 MHz: USB PWB IC3, pin 25)
(4 MHz: USB PWB IC3, pin 25)
Check clock generator
(USB PWB X1)
and its peripheral circuits.
(USB PWB X1)
and its peripheral circuits.
No
Yes
RESET
(USB PWB IC3, pin 6) is High?
(USB PWB IC3, pin 6) is High?
Check USB PWB R3, C203,
and D7.
and D7.
No
Yes
Data input
(USB PWB IC3, pins 7 and 8)?
(USB PWB IC3, pins 7 and 8)?
Check the path from USB
PWB CN1 to IC3.
PWB CN1 to IC3.
No
Yes
Data output
(USB PWB IC3, pins 9, 10, 12,
and 13)?
(USB PWB IC3, pins 9, 10, 12,
and 13)?
Check the path from USB
PWB IC3 to CN2.
PWB IC3 to CN2.
No
USB is inoperative.
Display