Rca 730tv1

[earlyfilm]

Originally Posted by John Folsom

Looks to me like you have a horizontal width problem, not a vertical linearity problem...??

John,

You are 100% correct!

With only the image of the test pattern visible and the height stretched, I had assumed that the RCA roundie was flipped on its side for under-the-chassis checking, but a quick enhancement of the picture to see what is hidding in those shadows reveals that this is not the case.

Let's see if I can undo my rather large goof.

On page 24 of the Sams, you will see the horizontal adjustments.

I would suggest checking or replacing your 6BG6 and then trying (count your turns so you can undo any changes) adjusting the horizontal linearity and see if that helps. Warning: These linearity coils sometimes freeze with age and if forced, you can break the tube. I would suggest a gentle test wiggle with the power off, so you can feel if the core is stuck or not.

If this adjustment seems to be addressing the right problem, and you have recapped and and tested all the tubes in the horizontal section, you might consider doing all the procedure on page 24, with this warning: A mistake in doing the horizontal oscillator adjustment can sometimes be very difficult for a learner to resolve.

James

[vts1134]

I think it is me that made the rather large goof, not you James. I thought the picture was stretched vertically so I misdiagnosed the problem as vertical linearity. I did not recognize that the picture could instead be squished horizontally, and therefore a horizontal problem. Interestingly enough when I adjust the width, as well as the horizontal linearity slug there seems to be no change to the picture. Both turn easily and were not stuck at all. The horizontal linearity coil looked a bit melty from the start and I suspected it might be problematic when I first laid eyes on it.

[M3-SRT8]

Width Controls seem to vary in sensitivity from brand to brand, set to set, etc.

The RCAs that I own of that same vintage (721TS, 721TCS, 630TS) seem to need quite a few turns of the Width Control before you get any change.

Now, my 1950 Zenith 12" Porthole, with the Width Control on a slider, is way more sensitive. You breathe on it and you get a change.

[vts1134]

Originally Posted by M3-SRT8

Width Controls seem to vary in sensitivity from brand to brand, set to set, etc.

The RCAs that I own of that same vintage (721TS, 721TCS, 630TS) seem to need quite a few turns of the Width Control before you get any change.

Now, my 1950 Zenith 12" Porthole, with the Width Control on a slider, is way more sensitive. You breathe on it and you get a change.

I'll give width another shot when I get back in front of the set.
Thanks for the first hand knowledge, it makes things easier and less scary for sure.

[Phil Nelson]

Don't be scared by a little bubbling on the wax around the coil. The big question is whether the windings have continuity and whether the adjuster has any effect at all.

Horizontal linearity is one of the more difficult things to get right on certain TVs (difficult for me, anyhow). Your linearity is noticeably off when viewing a test pattern. I doubt it is half as noticeable if you are simply watching a movie or TV show.

I would follow the instructions in the manual, as suggested, and then see how it looks.

Phil Nelson

[Penthode]

I suspect that all that is wrong is the 6BG6. Try substituting a new one.

[vts1134]

Originally Posted by earlyfilm

On page 24 of the Sams, you will see the horizontal adjustments.

A mistake in doing the horizontal oscillator adjustment can sometimes be very difficult for a learner to resolve.

James

You aint kidding!
Gosh did I get my self in trouble while trying to go through the oscillator adjustment. The width is much closer to being correct but I've completely destroyed the picture in the process.
I've given up for the evening because I started to get frustrated and will pick it back up tomorrow. An opportunity to learn oscillator adjustment thoroughly through thoroughly messing it up .
Edit: I have three horizontal output tubes, the two that tested good gave me pretty much the same results, another that I was unsure of gave me a severely degraded picture.

[vts1134]

Coming back fresh made a big difference. I dialed in the horizontal and figured out my problem. This is my first round screen set and I didn't have an idea of what the final picture dimensions should be. I measured the bezel on the cabinet and realized that I had the picture stretched out WAY too far vertically. After I dialed back the vertical size the picture became much more linear. It's still not perfect towards the top of the picture (as you can see by the clock at the top), but it's close enough for me to watch some movies on it and put it back in the back of the restoration cue and move on.

I installed the chassis into the cabinet and now my favorite TV in my collection is a working TV .