Read Sharp LL-T15S1 (serv.man7) Service Manual online
CHAPTER 5. 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
* Check LED for breakage.
* Check the path between JP2 (9pin) and
* Check the path between JP2 (9pin) and
U11(27pin).
* Check cable for disconnection.
Replace any unit (main PWB, SW PWB, cable
Power jack) which shows any defect, with a new
Power jack) which shows any defect, with a new
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) or power jack PWB?
3) EEPROM (U11) has +5V (VCC)?
4) LED
* Check LED for breakage.
* Check the path between JP2 (9pin)
* Normal?
* Connected properly?
2) Blown out fuse (F1) or power jack PWB?
3) EEPROM (U11) has +5V (VCC)?
4) LED
* Check LED for breakage.
* Check the path between JP2 (9pin)
and U11 (27pin).
* 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
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
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) Check if gate voltage is output normally.
3) Check if Source voltage 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.
<Voice output error>
+12 V DC at 1st and 2nd pins of JP1?
Signal input of 4th pin of U12 is at H level
(+5 V DC)?
(+5 V DC)?
Check mute input circuit of I/F board.
Input signal of 3rd and 5th pins of U12 is normal?
Check power supply, vo ice input and voice
input circuit of I/F board.
input circuit of I/F board.
Signal input at 1st and 7th pins of U12 changes
when voice volume is changed.
when voice volume is changed.
Check control PWB and the volume circuit
around U11.
around U11.
Signal output at 8th, 10th, 11th and 13th pins of
U12 is normal?
U12 is normal?
Check amplifier circuit around U12.
Check speakers and speaker cables.
• Check connection of JP1 connector.
• Check fuse F1 of Power Jack PWB.
• Check fuse F1 of Power Jack PWB.
