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[Update] Need help with a CRT TV

Ivan Ujkić

Nov 16, 2016
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Original thread: http://www.electronicspoint.com/threads/need-help-with-an-old-crt-tv.281322/

I didn't get around to fixing this until recently for various reasons... So now I cleaned a bunch more dust out and cleaned a bunch of connectors and the TV now powers on and does something, um, interesting i guess... I turn it on on the remote and it just shows a white blob at the bottom, and then very quickly turns itself off. I have a picture of it (the tiny white spots are just reflections).
tmp_4243-2017-03-19 20.35.17251221455.png
 

shrtrnd

Jan 15, 2010
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Not much to go on, but I would be checking for problems with the power supply.
The CRT televisions have a degaussing coil around the outside of the front of the picture tube. When you turn
the TV on, and when you turn it off, the degaussing coil fires a millisecond pulse to demagnetize the picture screen
so that the last image on the screen doesn't remain in the phosphors.
I'm thinking your 'interesting' phenomenon is just the degaussing coil pulse(?)
 

Ivan Ujkić

Nov 16, 2016
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The CRT televisions have a degaussing coil around the outside of the front of the picture tube.

Are you talking about this thing because yeah I forgot to plug it in and turned on the TV once (doh) and it worked fine but the next time i tried to turn it on I got something very similar and even though I put it back in and turned on the TV twice after that the same thing is happening...
tmp_31795-2017-03-21 19.48.00-1467048467.png tmp_31795-2017-03-21 19.47.101525473392.png
 

shrtrnd

Jan 15, 2010
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When you say it 'worked fine', do you mean you had a picture on the screen, or did you just mean that your degaussing function worked?
I checked your original post. davenn advised the set is probably a lost cause, and he is probably right considering the expertise required in trying to make the TV work again. There are just so many things that could be wrong with
electronics that sat outside exposed to the elements for so long.
Dirty water could have worked it's way into so many components that it's difficult to know where the problem or problems might be.
If you're going to continue with this, I'd re-clean the socket that connects to the pins on the picture tube (I assume you're using one of the contact cleaner spray cans for that), recheck all of the wiring connectors to be sure they're
clean, and then recheck the power supply section as that's where most problems occur that cause no picture on the screen.
It's difficult to say if you're going to get lucky with this set and whether or not you'll be able to fix it because of its
exposure to the outdoors.
Yes, your red markings on your pictures are probably the degaussing function. You know if it's working or not
because when you turn the set on and immediately after you turn it off, there is a strong static charge on the front
of the picture screen which would tell you that it's working.
I assume you realize that grandma probably put this set outside in the first place because it wasn't working. So even if you get everything right in cleaning off the dust and grime, you'd still be stuck with the original problem that grandma had which caused her to put the set outside.
 

Ivan Ujkić

Nov 16, 2016
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Yes, it did have a picture on the screen and I hooked it up to a portable DVD player and it worked. And no, she took it out of there along with a bunch of other stuff because we were repainting the walls. I guess I'll have to check out the power supply and clear out those sockets (I have an air compressor there).
 

shrtrnd

Jan 15, 2010
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That's GREAT news. Clean the wiring connectors and make sure they make good contact when you reseat them.
If it was working, you've got an intermittent connection somewhere and you just need to find it.
Tell her next time, just put the non-electronic stuff outside when she decides to repaint.
 
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