JVC 55" Rear-projection TV

Preventive maintenance on a picture tube?

I tried fixing a TV from the 90's once. I'm sure I could have done it, if it had been the least bit designed for mantenance. The damned back and bottom were molded together, so if you took off the back then it had no bottom (or support for the board, which was left dangling) and it kept threatening to fall back and crack the neck off. I decided it wasn't worth the bother or danger.

I was thinking the same thing, right after I recovered from imagining what it took to align that beast.

On tube type TVs. I did that for about nine months, in the US Army. They were used as video monitors/TVs in classrooms & Air Traffic Control Towers. where you wanted them to work to their design. Since those projection CRTS are know to leak after so many years, what is wrong with replacing them before they fail and damage the circuit boards?

It isn't that difficult, if you really want to fix one. That problem didn't start in the '90s, and was done on computer monitors as well.

Same here. The only easy access was to that alignment board (with those ~100 pots :) and the backside of the CRT's... the rest was accessible only by disassembly of the particle-board-bonded-vinyl case. ...Jim Thompson

Have you melted any coins or started a fire yet with the Fresnell lens? Wear two pairs of sun glasses or some cutting goggles, the hot spot is extremely bright. Mikek

I haven't tried it yet. But it's not circular... JVC calls it "lenticular".

It's what I would call a "grating". So I'd guess it would focus a line rather than a spot. ...Jim Thompson

I think you will find two layers, they come apart, one just lays over the other, one is a grating the other will be a Fresnell lens. The grating is on the viewing side the Fresnell is on the inside. Be careful where you store it, I'll bet there has been a fire somewhere from poor placement of a large Fresnell lens. Mikek

Hey Jim, did you find a Fresnell in the 55" tv? Mikek