Weak CRT On Zenith System 3 Console??

[bigskymusic]

Greetings 1st post here, a 1986 Zenith System 3 25" console followed me home yesterday only minutes away from being crushed up in a compactor at the local thrift store.

The cabinet is mint not a scratch dent or chip in it, but it was a smokers set, so it pretty nasty inside, a good cleaning should take care of it. Appears to be a higher end model.

It works and displays a good picture but some of the settings have me worried, the picture control has to be turned up to the max for a bright picture, If i tweak the fly-back it just gets washed out, is that normal? There is also a number of controls behind the flip down door that I don't what they do.

2nd issue is, after I tweaked the focus control, be clear and crisp while running, but on power up the picture is very very blurry and takes about 15 secs or so to clear up.

Is this a sign of week crt or just some caps and settings that need tweaking. I am using a 2002 27" RCA set for my bedroom TV and like it but I love the looks of this zenith and would love to use it.

Thanks for any and all feedback.

[Dreamsbeard]

A dim picture is often a sign of weak CRT, I've seen an aerly 80's Hitachi with exactly the same thing. Check if the red colour smears on the right side of the picture, that's also a sign of weak crt.

But hey, I'm not an expert, could be wrong!

[bigskymusic]

No, I have a seen a few do the smearing thing, but this one don't do that.

Originally Posted by Dreamsbeard

A dim picture is often a sign of weak CRT, I've seen an aerly 80's Hitachi with exactly the same thing. Check if the red colour smears on the right side of the picture, that's also a sign of weak crt.

But hey, I'm not an expert, could be wrong!

[lnx64]

Smearing only happens on transistor sets, not tube sets. I don't know if this TV is tubes or transistor.

If it appears washed out, turned down the brightness.

[davet753]

Check the picture tube and see what it looks like. I used to have really good luck rejuvenating weak Zenith CRTs. I've seen plenty of them where no matter what I did the picture just wasn't up to snuff...but cleaned up quite nicely after a little rejuvenation.

[bigskymusic]

Thanks guys, I borrowed a buddy's CRT tester, and the CRT is shot. I tired to rejuvenation it and it did not do anything.

[packrat79]

Zenith CRT's from that era delivered a great picture, but in my experience as a tech the larger ones were not very long-lived - fading out after about 8 to 10 years or normal use. If rejuvenation didn't work, you could try making your own filament winding if you know how to do that, and wire it to run just slightly higher than 6.3 volts. It will perk up the picture considerably but will greatly shorten whatever life is left in the CRT.
When tweaking the controls on the flyback, keep in mind that the screen control (the lower one) will brighten the picture but conversely shorten the life of the CRT. A better option is to turn up the R-G-B controls on the CRT board instead. There may also be a sub-brightness control somewhere inside the set.
Good luck.

[bigskymusic]

Thanks for all the help guys, I did try and tweak all the settings and focus controls, nothing made it look quite right, that combined with fact it's from a heavy smokers house, I just trashed it again.

Can't save them all ;-(

Originally Posted by packrat79

Zenith CRT's from that era delivered a great picture, but in my experience as a tech the larger ones were not very long-lived