NEC MultiSync LCD2080UX -BKA Service Manual page 116

TROUBLESHOOTING
TABLE OF CONTENTS
1. POWER is Not Available
2. No Picture Display ............................................................................................................ 6-3
2.1 Black Screen and LED is Amber ..................................................................................... 6-3
2.2 Black Screen, LED Green, and No OSM Present .......................................................... 6-4
2.3 Black Screen, LED Green, and OSM Present ................................................................ 6-5
3. Picture Errors .................................................................................................................... 6-6
3.1 High-Light Chroma in White or Black .............................................................................. 6-6
3.2 Images are Unclear ......................................................................................................... 6-7
3.3 Image Noise .................................................................................................................... 6-8
3.4 Color Errors ..................................................................................................................... 6-9
4. Other Operational Errors ................................................................................................... 6-10
4.1 DDC Read Error .............................................................................................................. 6-10
4.2 Back Light Malfunction .................................................................................................... 6-10
5. Switching Regulator Circuit Failure ................................................................................... 6-11
Note
Prior to the diagnostic servicing for troubleshooting, the following items should be examined to confirm the
freedom from abnormality:
(1) Power supply voltage: 100 to 240VAC
(2) Input signal: 1600 x 1200 (60Hz), recommended (Separate)
DVI 2-input
Display pattern
(3) All connectors should be correctly connected in the unit.
*1 With an ordinary oscilloscope, signal check is impossible to carry out. Confirm that the signal output
is normally generated, using a normally operating unit (a different model acceptable).
*2 For some types of video boards, digital signal output may fail to be generated unless the DDC is
read out on the unit side and the unit is confirmed to be a "digital compatible monitor."
<< Explanations below are based on the analog DVI input(input 1).>>
................................................................................................. 6-2
Analog RGB 0.7Vp-p (when terminated with 75Ω)
Digital TMDS *1, *2
Display not in black
6-1
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