Why do old trinitron tubes go green?

Trinitrons suffer a lot from falling emission, and are easy to repair. Boost the heater voltage, starting with +33%, and if not good enough go to +50%. This is a permanent heater voltage boost. On no account use those awful crt rejuvenator machines on these.

On an experimental set, in which none of the channels were even visible indoors in daytime I used +70% heater boost and IIRC +10% EHT boost and it survived and worked like that for years. EHT boost is not recommended unless you know the tubes x-ray limits, and are willing to accept a slight chance of it dying.

NT

Trinitrons often suffer from falling emission but are easy to repair. Apply +33% heater boost, and if this isnt enough apply +50%. This is permament voltage boost, not a rejuve. Keep the rejuve machine well away from them.

On an experimental set I used +70% heater boost (they ran yellow) and IIRC +10% EHT boost. It ran fine that way for years, but you cant do that sort of thing for other people. Dont boost EHT unless you know the tube's x-ray limit rating, otherwise you can go over that sometimes. When I got the set, none of the chanels were visible indoors in daytime, and I fancied a challenge. I was very surprised the set survived and worked, but it did, for years.

NT

I dunno how to do all that stuff. Is it dangerous? Easy? I don't even have a solder, nor do I have any experience.

Find someone who does, a TV is no place to learn the very basics.

then keep out of TVs and microwaves.

NT