Hey KB, if you're still checking out this thread here's some information from a totally amatuer non-electronically inclined guy whose abilities don't go past changing out tubes (but NOT CRT's--that whole high voltage thing scares me too much) and making adjustments.

My 325 had an ion trap originally and still does after having its CRT replaced many years ago, and I know it's necessary because adjusting it does have an impact on brightness. I think yours probably needs one. Not saying that will fix your problem, but I'm guessing once the problem has been solved, an ion trap will need to be a part of the finished and working product.

I'm considering a re-cap of my 325 by a local vintage TV/radio guy but am thinking even in working condition I probably wouldn't recover my costs when the set eventually goes up for grabs. And there's that open issue around the wrong channel selector knob. . .