LL-T1803 (serv.man8). Complete - Sharp Monitor Service Manual (repair manual). Page 12

LL-T1803-E/P

TROUBLESHOOTING

5 – 1

A

The power is not

supplied.

When the power switch is

turned,

does the LCD turn green?

Does the back light turn on?

NO

NO

NO

NO

NO

NO

YES

YES

YES

YES

YES

Check the analog cable input

and the digital cable input. 

Normal

Normal

Abnormal

Abnormal

Check each pin of JP4. 

Replace the analog/

digital cable(s).

Check the inverter PWB unit. 

(Note) When checking the output side,

be careful of the high voltage.

(1400Vrms when starting)

Check the output circuit to JP4. 

When     +12V is NG, main PWB

Replace the LCD module lamp.

Replace the

inverter PWB unit. 

The LED turns red. 

The LED turns orange. 

Check the LED for breakage. 
Check the path between 
JP2 (8pin) and U12 (24pin).
Check the cable for disconnection. 

Replace any abnormal part.

(Main PWB, SW PWB, cable)

Is the machine in the power save mode?
(Is the sync signal inputted?)
    Is the PC power turned off ?
    Is the RGB cable disconnected ?
    Is the sync signal not outputted from 
    the RGB cable ?
    Is the Input key set to the analog, 
    digital, input PC side ?

Is the sync signal inputted

to the main PWB?

Replace the analog

and the digital cables. 

Check the input power system. 
    AC adapter
      Normal? 
      Connected?
    Is +5V (VCC) supplied to MPU (U12) ?
    LED
      Check the LED for breakage.
      Check the path between JP2 (8pin) 
      and U12 (24pin).
      Check the cable for disconnection. 

Replace any abnormal parts.

(    AC adapter,    Main PWB,

    Switch PWB)