Toshiba 50H81 - dark, blurry display

I recently replaced the convergence ICs in my 11-year-old Toshiba 50H81 rear projection TV. All worked well for about a week, then suddenly while watching Netflix streaming video from my son's Wii game console the picture went very (but not completely) dark and quite blurry. Sound was unaffected.

I get the same dark, blurry picture on all inputs (both standard and YPbPr component inputs) as well as through the built-in analog tuner fed with RF on channel 3 from a combo DVD/VCR player. For example, the main screen on the Wii, which is normally a fairly bright off-white, is nearly black, but the outlines of the buttons are shown in dull, blurry red or blue. The parental lock intro screen the DVD/VCR combo normally puts out with a greenish background with yellow/gold lettering is now blue with blurred, black lettering.

Interestingly enough, the on-screen menus all display perfectly - the colors are all good and the convergence grid displayed in service/maintenance mode shows that all three colors display across all sections of the screen the same as they did before the current problem developed.

There was a mild thunder storm going on when the picture went dark, but I doubt that is related because the surge suppressor into which the TV was plugged didn't trip and the router through which the Netflix streaming video was coming didn't so much as hiccup - my son was web surfing on his laptop when all this happened and his session suffered no interruption. The TV is not directly connected to any outside antenna or wiring.

I suppose it's possible that I stressed a connection or solder joint while replacing the convergence ICs, but what I'm seeing here is obviously a completely different problem from the convergence issues I fixed earlier.

I'm going to pull out the signal board again to see if there are any obvious signs of damage, but I thought I'd ask for any suggestions before getting in too deep. Given that the on-screen menus display correctly, I think the problem may lie in the signal board or the input board on the back of the TV that plugs into the signal board.

I will greatly appreciate any suggestions or guidance. Thanks!

Darron