CRT TV/Monitor Repair & Troubleshooting

I picked this 20m4u up for free a while ago and just got around to messing with it. Whats happening is the screen will turn on and change colors then cuts off. There is still power and you can hear a clicking sound from the tally light. Video below. Any ideas?

I’d hazard a guess at a flyback issue. The focus pot on it at the very least is set way too high.

Reviving this thread to talk about something specific that we’ve all seen.

Flat screen (and some curved) CRTs almost all have a slight to severe bowing upwards of the picture.

Anyone have experience in fixing this? Supposedly it’s due to a sagging of the yoke over time, and can be adjusted by opening up the TV and fixing the alignment of the yoke.

Sorry for the bump but I didn’t want to clog up any other threads.

@Gravitone suggested I try applying some window tinting film to my JVC1710cg monitor that had the protective film removed by the previous owner.

I did a quick and dirty job today to see if it was even worth doing. This JVC is a bit of a pain and requires you to disassemble the set completely to remove the bezel - so rather than commit to a few hours of work I decided to do just slap some film over the top as a bit of a test.

These photos were taken in the absolute worst conditions possible. It’s a 36 degree day here (about 97 Fahrenheit) - and my partner had all of the window shades open to let light into our kitchen so it was incredibly bright.

These are the results of the experiment film on the left, pure glass on the right (please excuse my miserable application job):

As you can see - the difference is rather striking.

This film was VLT35 meaning it only lets 35% of the light through - and is a little dark so I’ll be going with VLT50 that I also picked up. That said you can easily mitigate that by cranking up the tube brightness (which I’m hoping to avoid).

So it looks like a job definitely worth doing! - we’ve got a long weekend coming up so that’s plenty of time for me to disassemble the monitor and obsess over every tiny detail.

If I have any success I’ll post my results here - thanks for reading!

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That is a huge difference, well worth the effort if you ask me

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Oh definitely - this photo is probably an even better example:

The monitor only has 7k hours and was manufactured in ‘08 so it is incredibly bright but without the anti glare film installed in a well lit room you have no blacks at all.

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Did a test with the 50VTL and it looks incredible. Much better than the 35VTL.

Hoping to apply it next weekend when I’ve got some spare time to tear down the monitor.

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So I’m a bit embarrassed. I cleared the deck to tint the tube this morning - everything went swimmingly, discharged the tube, broke down the monitor:

Aaand I stripped the final screw I needed to remove the tube from the bezel. On the bright side it’s a bolt screw but of course I don’t have a flexible head wrench small enough for it. I’ve ordered them on Amazon but I had to admit defeat today.

Taking it apart is quite a bit of work so I’ve left it disassembled for now.


That was a bit of a waste of a morning!

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Respectfully, I disagree. You learned how to disassemble the monitor and had the mental clarity to know when to stop and not force things (aka break things).

Unrelated, I like your wood floors and “tongue and groove” walls, and the color. Everything in the US now seems to be so generic. I think you’re in Australia, from previous posts.

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Thanks! I’m glad cooler heads prevailed I was considering getting some pliers and trying to force it. You’re right though - I’m now way more comfortable disassembling a monitor. For the longest time it was something I always avoided out of fear but now I can safely discharge it, break it down and put it back together.

As for the walls thanks! I love tongue and groove, only in the bedrooms but it gives things a more organic feel, and yep located in Australia!

Also I’ll do a proper post when I get a chance to take some more photos - but I had some success with the correct tools:



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