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baron baron is offline
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Default Strange LCD repair outcome

Meat Plow Inscribed thus:

On Sun, 27 Dec 2009 09:57:11 +0800, pedro wrote:

I normally repair LCD monitors which are heading for landfill, and
they are turned over to needy/worthy groups (usually replacing olde
CRTs). Almost always, repairs are either "recap SMPS" or "replace
inverter transistors", and the hardest part is getting the case apart.

Recently one Samsung 943NWX - presented as "dead" - had an odd
outcome. Replaced the bulging electros in the PSU and the unit came
to life, but with a dominant pink tinge to the entire screen area.
Normally I would ascribe this to backlight end-of-life, but three
things contradict this diagnosis. Firstly, hitting the menu button
with no video drive gives a small display "Test OK" (or similar) text
on a background which is white, so backlight colouration is unlikely.
Ditto if the menu system is fired up when a video signal is present -
pink screen but the menu b/g is pure white. Clearly the VGA input is
being incorrectly processed. Finally, the donor has confirmed that it
was white before failure.

Has anyone experienced the video processor taking a hit when the SMPS
goes west with faulty caps? Clearly the unit doesn't warrant pursuing
a video chip replacement, and thereare no signs of distress on the
video board.


Maybe something you did while servicing? I wouldn't look for faulty
caps in the smps to cause anything but a fail of the smps.


A possible cause is the user settings got cleared in the flash chip
whilst replacing components.

--
Best Regards:
Baron.