I installed a new blue out polarizer (the one sandwiched between the LCD and prism on the "optical block"). I would write up instructions, but the task is difficult and my results were disappointing.
I had severe yellowing in the center and had developed some blue blobs on the top edge of the screen. Before repairing my ax200u, I practiced on an old ae700u. The ae700u had developed the blue blobs due to a bad blue LCD so I've seen this before. I hoped that the blue blobs on the ax200u were something other than the LCD, but they weren't. In fact the blobs are much worse now, extending across the top and through the center of the screen. It seems that the bad polarizer was helping to correct the degraded blue LCD. I'm probably going to replace the good polarizer with the burnt one because I can tolerate the yellowing much better than blue blobs.
I examined and adjusted the blue incindence "in" polarizer (the one mounted with a screw between the "optical block and the lamp). It doesn't rotate enough to really make a difference in the image so the adjustment here isn't crucial. All it does is reduce the amount of light that passes through the blue LCD. When I examined it under a strong light I could see an outline of where the light hit burned into the polarizer, but it was not burned so bad it changed color like the out polarizer. If you do remove this, scribe a line so you can put it back in the same position.
My ax200u has 4572 hours total and is on its second bulb. Most of the time I ran it in high altitude mode (faster fan) but I don't think this helped.
My opinion after owning two Panasonic projectors is that sometime after the warranty expires, the blue LCD will fail. I was pretty bummed about it, but a friend who is also in to projectors set me straight. I was lucky to get as many hours as I have, and it was glorious while it lasted. I think the real reason I'm upset is that there isn't a new 720p model available and I don't think I'm ready to make the jump to 1080p.
For those of you that still want to replace your polarizer, here are links to manuals that I found on the net:
The method is the same as the ax200u, the polarizer part numbers aren't. To get the correct part numbers, use the ae900 numbers, but change the number after G from 10 to 20 (66G20 where the manual lists 66G10). Where the manual calls them Combination 1 & 2, the parts site lists A & B. I have a L3D07H-66G20 blue LCD so I ordered the TKGP5329 Polarizing plate/out(B) B.
AE700 polarizer replacement:http://www.dvdplaza.fi/forums/attach...2&d=1173395643
Order your parts from here:http://www.pasc.panasonic.com/ePartr/
My polarizer was $114 shipped.