LL-T18A1 - Sharp Monitor Service Manual (repair manual). Page 13

LL-T18A1

TROUBLE SHOOTING

5 – 1

The power cannot be turned on.

The LED lights up in green when
the POWER SW is turned on.

NO

NO

NO

NO

NO

NO

YES

YES

YES

YES

YES

The backlight
lights up.

Check the input signals of
analog and digital cables.

Normal

Normal

Abnormal

Abnormal

Normal

Abnormal

Analog/digital
cable conversion

Check the inverter PWB.

When checking the output side, 
be careful of the high voltage.
(When starting: 1400V-rms)

Note:

Replace the LCD module lamp.

Replace the inverter PWB unit.

The inverter cable is connected.

The inverter cable is damaged.
Check the outputs on JP3 pins.

Replace the unit where an abnormality
occurs. (Main PWB, cable)

The LCD lights up in red.

The LED lights up in orange.

The LED is damaged.

Check the path between
JP2 (8pin) and U4 (120pin). 

The cable is disconnected.

Replace the unit where an abnormality
occurs. (Main PWB, SW PWB, cable)

The machine is in the power save mode
(the sync signal is not inputted).

The power of PC is turned off.
The RGB cable is disconnected.
The sync signal is not outputted
from the RGB cable.
The "Input" key is set to the analog,
digital, input PS side.

The sync signal is inputted to the main PWB.

Analog/digital cable
conversion.

Check the input signal.

AC adapter

Normal ?
Connected properly ?

+3.3V is applied to U4.

LED

The LED is not damaged.
Check the path between
J2 (8pin) and U4 (120pin).

The cable is disconnected.

Replace the abnormal unit. 

AC adapter

Main PWB

Switch PWB