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Old 04-22-2019, 04:00 AM
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MadMan MadMan is offline
The Resident Brony
 
Join Date: Oct 2016
Location: Chicago
Posts: 1,218
2 years later update!

This thing's been sitting on its side in the middle of my bedroom for the past 2 years. I've been struggling with this stupid horizontal linearity problem. The left side of the picture was stretched out, and no matter what I did, it just didn't work out. But today I decided to take a fresh look at it, I tried a bunch of things, poked a bunch of stuff, and it was a little frustrating, but then something clicked. I'd been focusing on the linearity area. Mind you, I've never repaired or adjusted a tv like this before. But I decided to start messing with other stuff related to horizontal.

Wouldn't you know it, the horizontal drive trimmer was the culprit this whole time. It was about 99% tight, and if I loosened it, it worsened the stretching on the left side. So I figured that if I add a capacitor in parallel, it should either make it worse or better, either way, that was the culprit. I dug up a 22pF disc cap, put it on, and it happened to be just about right. I could now adjust the H drive to get the picture almost 100% linear.

It's still not 100%, but you know, 99% is pretty good for a 70 year old tv. And I'm quite proud of myself. :3

I'm imagining a 1kv ceramic cap would be acceptable for that area? I was considering replacing the actual trimmer, but it still works, I think maybe it's simply drifted to a lower capacity? Idk. Also, there's a bit of a neck shadow in the lower right corner, but I've given up on that. Doesn't bother me much, anyhow. You can see the stretched out test pattern here.

Now onto another project, I'd like to add RCA inputs. Any good threads on the topic?
Attached Images
File Type: jpg finally fixed 1.jpg (78.1 KB, 64 views)
File Type: jpg finally fixed 2.jpg (54.2 KB, 53 views)

Last edited by MadMan; 04-22-2019 at 04:04 AM.
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