The Backlight Does Not Light Up; Sound Is Not Outputed/ Output Sound Abnormality - Sharp PN-L803C Service Manual

4. THE BACKLIGHT DOES NOT LIGHT UP

When the power is turned on, the backlight lights up for
several seconds.
No
Is BU5V outputted from the 5V Power Supply PWB?
Are BU12V and 13V outputted from the LED Power PWB?
Yes
Check the Main PWB and the related parts for any
abnormality.
- Check the connection cable.
- Check the fuses (12V Power : F2101,
13V Power : F2102) for breakage.
- Check the PWB.
Yes
- Check the connection cable.
- Check the Power PWBs.
- Check the output voltage of the LED driver.
- Check the backlight LED.

5. SOUND IS NOT OUTPUTED/ OUTPUT SOUND ABNORMALITY

Is the sound volume is set to the minimum or mute?
No abnormality
Is input selection set to audio signal input?
Yes
Check the audio input signal for any abnormality.
- Check the cable connection.
- Check the audio cable.
No abnormality
Check the Main PWB and the related parts for any
abnormality.
- Check the connection cable.
- Check the fuse (AMP Power : F2300) or breakage.
- Check the PWB.
No abnormality
Check the audio output cable for any abnormality.
- Check the cable connection.
- Check the impedance of the audio cable.
- Check the audio cable.
No abnormality
Any defect with the internal speaker and related devices?
- Check the speaker cable.
- Check the speaker.
No abnormality
Any defect with the external speaker and related devices?
- Check the speaker cable.
- Check that the impedance and the rating of the speaker
are proper.
- Check the speaker.
Abnormality
Abnormality
Abnormality
No
Abnormality
Abnormality
Abnormality
Abnormality
Abnormality
PN-L803C/80TC3 TROUBLESHOOTING 7 - 3
Yes
Refer to "3.THE DISPLAY DOESN'T
SHOW/DISPLAY ABNORMALITY".
No
Replace the abnormal part.
Replace the abnormal part.
Readjust and reset.
Select the input source properly.
Especially about HDMI and Displayport input,
check that the OSD settings fit with the audio
output settings on the source side.
Replace the abnormal part.
Replace the abnormal part.
Replace the abnormal part.
Replace the abnormal part.
Replace the abnormal part.