Is this close to what you are working on?
Gateway, it seems is also made by Samsung, and they post some of the service manuals for Plasma sets on their website. A Google Search turned up this one:
http://support.gateway.com/s/Manuals...TW-P42M203.pdf
LG, I could help greatly. With Samsung, it's always been about dead sets and 35V electrolytics - 470, 680 and 820uf, along with any others that are obviously bad.
Cheers,