I bought the projector from a local installer, rather than the Internet like I typically buy audio/video stuff, for this exact reason. My local guy is very helpful so I'll call him on Monday if you guys think it is a dust ball.
Well, it's something. Hopefully dust, which is probably better than a failing panel (not that I know what that looks like).
I just checked my filter and it is almost spotless.
My listening room has a Trane CleanEffects air filter. I get some dust, but, barely any. My lens is even pretty spotless and I haven't cleaned it recently.... I wonder how dust got in there?
Do you smoke while watching movies? If so, I imagine the rising/hanging smoke would get sucked in easily by the PJ, due to the proximity.
I looked in the manual, nothing about dust blobs.... but searching 'dust blobs' on google presented a lot of people that have had similar issues.
I send my Canon in to get cleaned once a year, so, I guess projectors are the same way?
I don't think you can categorize PJs so easily like that. Some PJs just get dirty easier than others. 3LCD is the most prone (well, there are 3DLP, but I don't know, and those are mega bux anyways).
You could try your hand at cleaning it yourself. There seem to be two camps. The "try cleaning it" camp. And the "better be careful because you might make it worse" camp. I looked in the 7500 owners thread at AVS, and there has only been one single instance of a dust blob, and it was described in the same way as adk highlander's: he can see it on a black screen.
Here is a guy who simply cleaned his Pana 2000 thru the air vents, and it worked for him. Other(s) tried with success as well, however, again you'll see the "better be careful" camp chiming in.
http://www.avsforum.com/avs-vb/showthread.php?t=958634
Hm, this might not be a dust blob though. Yeah, I'd post a pic at forums. BMX will know. It seems other large blobs have been diagnosed as other things such as a burnt polarizer or optical block, which can be a very expensive thing to deal with (good thing Epson has a good warranty). Then there is also the burnt LCD panel (though some would say extremely unlikely if inorganic, which I assume the 7500 is).
Ok, it looks like to see if it's a polarizer, you have to take them out and see if they have a burnt spot, discolored. If uniform, then they are fine. Polarizers seem to be in the ballpark of $100 a piece.
Long story short, take a couple of pics, bring it to your dealer, have it repaired, and see if he has a loaner PJ. Maybe a nice RS35 or something.