Eliminating This Problem on CRT

[masek]

Hello all,

I am trying to enjoy some beautiful gaming on a CRT I have. However, on darker - greyer - scenes, I notice these thick faint horizontal bars going across the screen.

I was able to make them less noticeable to my eye by toning down brightness, and sub brightness. At first, I thought it was an issue with green cutoff. But reducing green cutoff does not appear to have an effect. The bars are much more noticeable when the TV first turns on before warmed up and the screen has a lot of green. They also appear to completely disappear then I turn off the green gun.

The TV is a Sony WEGA KV-32FS320. Hopefully the attached image helps to see the problem better and doesn't make me look crazy.

If anyone knows of a more knowledge forum regarding CRTs please let me know.

Thank you!

[Xer Xian]

Might be retrace lines..

https://www.repairfaq.org/REPAIR/F_monf ... MONFAQ_014
http://www.electronicsrepairmadeasy.com ... n-crt.html

[masek]

The lines do not appear to be retrace lines. At least from the examples of retrace lines that I have seen. The bars are thick, and appear to be perfectly horizontal. They are also very faint, and only seem apparent in a grey picture. I posted an image, but for some reason it is not showing up.

[masek]

Here is the image: https://imgur.com/a/7Dnwb

Can u see the alternating light and dark bars in the pattern?

If you look close enough you can actually see the pattern in video black. Toning down the sub brightness made this more difficult to see though.

[masek]

Here is another that may help: https://imgur.com/a/KHbS6

It appears the bars have a green tint to them. When I turn the green gun off, I can no longer see them. I'm not sure what in the circuit would cause this, as lowering green cut off does not fix the issue.

Edit: sigh, I didn't realise imgurl would compress it so bad u can not make out anything useful.

[masek]

I uploaded to bitbucket a higher quality image: http://i557.photobucket.com/albums/ss19 ... qibe4p.jpg

[Xer Xian]

Yeah definitely not a retrace issue. It doesn't look too bad though, your TV probably needs some run-of-the-mill servicing like looking for bad caps, loose or dry solder, etc. Sorry for the being so vague - there are members here with first-hand experience on reparing CRTs, but I'm not one of them..

[masek]

Thank you for the help. Even though it doesn't appear to be a retrace issue I'm going to follow some of the guide you posted and try adjusting G2 to get a lower background level and see what kind of effect that has. Lower subbrightness helped make it less noticeable, but stopped helping past a certain point.

I did see a cap that looked like it could have been leaking, but I blew it out with dust before inspecting closely. I did not see any bulging. The cap was near the fly back or psu as I recall.

[DirkSwizzler]

I did see a cap that looked like it could have been leaking, but I blew it out with dust before inspecting closely. I did not see any bulging. The cap was near the fly back or psu as I recall.

Caps can still be bad without bulging. Bulging just happens to be the easiest way to spot one that’s definitely bad.