Re: Sharp LL- T17A4-B lcd Monitor

On Thu, 12 Jun 2008 12:04:02 -0500, jakdedert
<jakdedert@xxxxxxxxxxxxx> put finger to keyboard and composed:

Bought from the 'E' place for cheap. Reported symptom: video comes on
and fades out. Figured it was high ESR smps caps.

Actual symptom: backlight comes on, image consist of random horizontal
lines, which eventually--after some intermittent vertical
scrolling--settle into a very nice image. Takes like two minutes to
warm up. Shutting the monitor down for some unknown time starts the
process all over again. Continuous viewing yields a stable image with
good resolution, brightness and linearity. Shutting down for short
periods is not problematic.

There is only one HV (100 @ 400v) cap in the ps. ESR is .46, which I
assume is within tolerance. Other caps in the ps also seem fine.

This presents so like a classic cap issue (needs to warm up), that I'm
going to next pull the video board and check caps there...possibly get
some freeze spray and see if I can duplicate symptoms that way.

Reality check: any problem with the above procedure, or experience with
this particular monitor? Any suggestions as to where to go if the above
doesn't produce a dx and fix?

Thanks as always,

jak

FWIW, that monitor came with a 3-year warranty.

If that is not an option, then I'd be hooking up your scope to the
horizontal and vertical sync inputs and following them through. It may
help if you told us which chips are used, eg Genesis Microchip.

Have you considered that the video source may be just outside the LCD
monitor's range? I sometimes find that a 75Hz refresh rate is right at
the limit before the monitor blacks out. Try a safe 60Hz refresh rate.

What about the OSD? Is it stable? Pull the RGB cable and watch the "No
Signal" OSD window, or whatever your monitor reports.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
.

Relevant Pages

  • Re: Sharp LL- T17A4-B lcd Monitor
    ... Actual symptom: backlight comes on, ... Shutting the monitor down for some unknown time starts the ... Other caps in the ps also seem fine. ... ESRd all caps on video board. ...
    (sci.electronics.repair)
  • Re: Viewsonic VP201b problem continues.
    ... Have problem with picture rotating from top to bottom. ... One place I repeatedly suggest people with monitor problems visit is ... I would look for other bad caps in the power supply. ...
    (sci.electronics.repair)
  • Sharp LL- T17A4-B lcd Monitor
    ... Actual symptom: backlight comes on, image consist of random horizontal lines, which eventually--after some intermittent vertical scrolling--settle into a very nice image. ... Shutting the monitor down for some unknown time starts the process all over again. ... Other caps in the ps also seem fine. ... This presents so like a classic cap issue, that I'm going to next pull the video board and check caps there...possibly get some freeze spray and see if I can duplicate symptoms that way. ...
    (sci.electronics.repair)
  • Re: k7000 Rant
    ... changed all the caps, reflowed the yoke wire connector and rgb pins. ... time to troubleshoot for cold solder joints and lifted pads. ... The K7000 seems to be the monitor I most often ...
    (rec.games.video.arcade.collecting)
  • Re: SOT: What would cause this video game monitor issue?
    ... WHAT KIND OF MONITOR IS ... Most vertical problems are capacitors. ... If this is the case for sure is caps. ...
    (rec.games.pinball)