Sharp LL-T15A3 (serv.man6) Service Manual ▷ View online
LL-T15A3
TROUBLESHOOTING
4 – 1
CHAPTER 4. TROUBLESHOOTING
5) Check connector of power jack PWB
for breakage. Check the cable for
disconnection.
disconnection.
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
Yes
Yes
Yes
Yes
Yes
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) on main PWB?
3) EEPROM (U11) has +5V (VCC)?
4) LED
* Check LED for breakage.
* Check the path between J5 (5pin)
* Normal?
* Connected properly?
2) Blown out fuse (F1) on main PWB?
3) EEPROM (U11) has +5V (VCC)?
4) LED
* Check LED for breakage.
* Check the path between J5 (5pin)
and U11 (27pin) or J5 (6pin) and U11
(26pin).
(26pin).
* Check the cable for disconnection.
Replace any defective unit.
[ 1) Adapter, 2) A Main PWB, 3) Switch
PWB, 4) Power jack PWB] with a new one.
[ 1) Adapter, 2) A Main PWB, 3) Switch
PWB, 4) Power jack PWB] with a new one.
Backlight turns ON?
Check for RGB cable input
signal.
signal.
Replace RGB cable.
Check each pin terminal
of JP5.
of JP5.
Normal
Normal
Normal
Defective
Defective
Defective
Check output circuit to JP5.
1) If +12V is NG, replace main
1) If +12V is NG, replace main
PWB.
* Check inverter PWB unit.
Note: Use caution when checking output
Note: Use caution when checking output
side because it has a high voltage.
(1400 Vrms when starting)
(1400 Vrms when starting)
Replace LCD module lamp with
a new one.
a new one.
Replace inverter PWB
unit with a new one.
unit with a new one.
A
LL-T15A3
TROUBLESHOOTING
4 – 2
Check the LCD control signal and
microprocessor control circuits around U1, X1,
U11, U8 and U9.
microprocessor control circuits around U1, X1,
U11, U8 and U9.
A
Screen does not operate normally.
Check RGB cable.
Defective
Replace RGB cable with
a new one.
a new one.
Check screen condition by changing display modes.
Reset the microprocessor 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 is output.
2) J6 Nos. 57, 58, 59 and 60 pins signal
1) Check if module control signal is output.
2) J6 Nos. 57, 58, 59 and 60 pins signal
outputs show DC+5V?
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.
Cable defective.
Cable defective.
Display
