(UPDATE 25 Oct 2010 - I have added another article with additional details on the subject. Find it here.)
(UPDATE Dec 2012 - now the Y-Main and a set of brand new, Samsung OEM buffers is available at our store.)
(UPDATE Feb 2013 - our store now has listings for both the upper buffer LJ92-01202A and lower buffer LJ92-01203A - used, but tested and functional, offerred as-is; make sure you read this article and offer description before buying!)
Here's a very simple and easy method of identifying burned buffer boards LJ92-01203A / LJ41-02761A and LJ92-01202A / LJ41-02760A.
Those are the buffers for Y-sustain LJ92-01200A.
The trio is used in a great number of 42'' plasma TVs using Samsung plasma display technology (the display itself and the sustain/buffer boards).
Now, to the point: The most common defect in those buffers manifests itself in burning and shorting the power lines and some output lines.
The easiest way to detect if a board was burned is to measure the resistance between its power input and ground.