Vintage 4.5" CRT emits cracking noise, I'd love to fix it

This might sound funny, but I'd like to repair a vintage 4.5 inches black and white small CRT tv. I got it yesterday from it's original owner, I tested it during the transaction, but didn't detect the defect before I was home.

The symptoms are :

  • The flyback transformer emits long sequences of cracking sound (1 or 2 minutes), like if it was internally arcing. Each sequence is isolated by no cracking at all. There's no visible arc, I turned all lights off and I assert, no arc is visible.
  • I can't detect any ozone or burning odor.
  • When there's a signal on the UHF port, the image is not filling the screen, it's vertically compressed.
  • The image is blury, and when the transformer emits a sound, the beam does a "kind of" vertical sinus line wave starting at the top of the screen, and ending at 1/3 from the top. (Probably the duration of the discharge)
  • The sound is correct and everything else is working properly.

I'd love to meet someone who knows how to fix these TVs. Of course I know they are probably rare now. I have no expectations, but it would be sad, the object is pretty, I mean, the design of it is vintage and looks great for its time, such a nice object isn't allowed to be trashed away. Thus, the cost of fixing it isn't a concern to me.

I'd like to know :

  • Can it be fixed in 2017?
  • What problem is it likely to be?
  • Is there a reference/guide on repairing such devices, I found informations on youtube and some website, but I'm not enough knowledgeable in electronic to debug this without help using these.
  • If I can't fix it myself, who could do it for me?

Edit :

@oldturkey03 found :

TV was marketed in the USA as a Cosmo 4.5" Portable Mini Personal Television TV-600-05. Cosmo Communication out of Miami Fl was an importer of "inexpensive" electronics made in the ROK.

Thank you!

Some photos :

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Contestado! View the answer Yo también tengo este problema

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Btw, I know how to solder, how to use a multimeter and I understand the basics of electronics.

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@modernbison and just to make sure you do know that CRT's carry enough power to zap you extremely hard! Just making sure while we are trying to figure this out:-)

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Thank you for the warning. I'm very cautious about it.

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Okay going by your description and the pictures I'd be looking at the vertical deflection IC's and caps. Let's see if we find a schematic for the board.

In the meantime it looks like you have about 3 or 4 IC's on your board. Any chance you can tell us the manufacturers numbers labels etc. on those?

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How do you find a schematic for a white labeled product?

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Reparte el espíritu de reparación esta Navidad
Obtén $12 de descuento en tu compra de $50 o más con el código FIXMAS12
Reparte el espíritu de reparación esta Navidad
Obtén $12 de descuento en tu compra de $50 o más con el código FIXMAS12

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Looks like a fun project and you did right to ask @oldturkey03 for help. When I used to work on these the main issue that repaired many were just simple cold solder joints. I'd go over the board with some good silver solder and a solder gun and see if your issues are resolved.

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Yeah! Sure, I'm learning how these tv worked and how to debug electronic problems. I learned electronic theory, but never played on a real board. It's pretty interresting.

Pending the arrival of the ESR tester, I will secure the joints. As @oldturkey03 and @pleriche suggested that vertical deflection circuit seems to be the culprit, I'll secure the solder joint from there.

Very helpful, thank you!

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Emmanuel estará eternamente agradecido.
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