Projector parts are not universally interchangeable. You will have to find THE one that is DESIGNED for your model(s). As far as which assembly is the ballast, it is the one with the heavy leads going to the lamp.
As posted elsewhere, you will get NO help from Dell. No manuals, no parts, no schematics, no information. They are useless. In fact, very few manufacturers even have schematics for their projectors, most replace the assembly instead of performing component-level repair.
I understand you're capable of repair. So am I, as an a/v tech with 25+ years of experience, but if NO information is available and the really significant components are proprietary and unavailable and some of those are SMD, what can you do?
It's going to take someone with a 3300 that has opened it or is willing to do so just to get the part numbers of the ballast to compare to yours. That's the way it is. Either that or gamble the $50 to get the damaged 3300 and hope it works.
And in all my searching I have yet to find a source for Dell parts. And I could really use them, I have 3 2400MPs in my shop that are destined for the dumpster because I can't get the simple parts to repair them. Color wheels, that's all I need, but they are not be found anywhere.
well thanks for your info, I was wondering if i got some high quality pictures this Thurs and posted them here if you could point out the ballast and maybe help me find a replacement one that will work.