LL-T1500A (serv.man15). Chapter 4 Troubleshooting - Sharp Monitor Service Manual (repair manual). Page 2

(2) <An error occurs when using Power Save mode>

Is the signal input of the 42nd pin of
the U10 at low level (0 V)?

No

Check the microprocessor control circuit
for the U10.

Check the operation PWB and related
parts (LED and cables).

(3)  <Backlight goes out improperly>

Is the 5th pin of the JP2 at DC+12V?

Check the CD+12V power line (12 V) and
the power supply circuit for the JP2.

Is the signal input of the 26th pin of
the U10 at low level (0 V)?

Check the microprocessor control circuit
for the U10.

Is the 1st pin of the JP2 at DC+5V?

Check the DC+5V power line (5 Va) and the
power supply circuit for the U17.

Yes

Yes

No

No

Yes

Yes

No

Check the inverter PWB unit.

Check the lamp inside the LCD module.

(5) <USB error>

Is DC+12 V outputted from the
power supply unit?

Check the power supply unit and
fuses (power supply unit).

Replace the USB unit with a new one.

Yes

Yes

No

No

Yes

Are the 1st pins of the inverter PWB
units CN2 and 3 at about 1500 Vrms?
(Use due caution not to get an electric
shock accident. For measuring the
voltage, use a high-voltage probe of
more than 100:1. )

Is the 26th pin of the U17 at 0 V when
the backlight luminance is at the
maximum (OSD BRIGHT31)?

Check the operation PWB (operation PWB
and cables) and the microprocessor control
circuit for the U10 and U17.

No

No

Yes

Is the 3rd pin of the JP2 at 0 V when the
backlight luminance is at the maximum
(OSD BRIGHT31)?

Check the backlight control circuit for the JP2.