Zenith A1512J restoration

[Kevin Kuehn]

Originally Posted by IsthmusTV

But the range of adjustment was relatively small. I don't think that it would be enough to fill out the width in your case.

I agree about the adjustment being minimal. I think I'd first take a look at the horizontal drive signal or horizontal output.

[Phil Nelson]

I experimented with a width sleeve when restoring my Capehart-Farnsworth 661-P. This article includes some explanatory paragraphs from an old TV service book:

http://www.antiqueradio.org/Capehart...Television.htm

The book says the ground connection is to prevent arcing from the sleeve to yoke windings.

In my casual experiments, pushing the sleeve in and out had quite an effect (granted, this was on a TV designed to use a width control, not a sleeve).

I don't see a sleeve in Bob's photo, only a ring. Is the sleeve pushed all the way into the yoke so that it's not visible?

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

[bandersen]

Originally Posted by Phil Nelson

... I don't see a sleeve in Bob's photo, only a ring. Is the sleeve pushed all the way into the yoke so that it's not visible? ...

Bingo I need to take the set apart again and dig it out

[bandersen]

I found it


That's better Thanks for the quick help guys

[Eric H]

It's hard to understand how a thin piece of non ferrous metal can affect the magnetic field enough to cause that much of a problem.

[Kevin Kuehn]

Yeah, that was pretty dramatic. That really shows how big of a problem a single turn short in the yoke would be. The service book Phil referenced said they came up with that idea in the late 50's, however my Setchell Carlson 25 chassis had a width sleeve as early as 1951. I wonder if Bart came up with that idea before its time.

[bandersen]

I was quite surprised it had that much of an effect too. The height also increased about 20% with the sleeve slide back into it's original position.

[Phil Nelson]

When I experimented with a (copper) sleeve, it was able to block the sweep completely.

Phil Nelson

[bandersen]

That reminds me of this neat YouTube video showing how a rare earth magnet reacts with different metals. http://www.youtube.com/watch?v=VEIYXomRdLY

[Kevin Kuehn]

Great video.

[dieseljeep]

Originally Posted by bandersen

Does anyone know where I can get twist tab panel mount pots like this ? AES only has 250K and 500K, but I need 25K and 750K.

http://www.tubesandmore.com/products/R-V500K-N2

I would try soldering a control nut on the original pot mounting plate.
Then you can thread on the replacement pot. I've done it before.
Get out the old 200 watt American Beauty.

[bandersen]

Why did you need to solder it to the plate ? I can just tighten it down with a wrench. The issue I have is that the pot shafts can only stick up about 3/8 of an inch from the mounting plate.

My AES pots arrived today. They're nearly identical to the originals except the shaft is too long.


A Dremel tool and cutoff wheel took care of that.


Much better

[dieseljeep]

Originally Posted by bandersen

Why did you need to solder it to the plate ? I can just tighten it down with a wrench. The issue I have is that the pot shafts can only stick up about 3/8 of an inch from the mounting plate.

My AES pots arrived today. They're nearly identical to the originals except the shaft is too long.


A Dremel tool and cutoff wheel took care of that.


Much better

My reasoning was to solder the nut to the bottom of the original twist mounting plate. That was the intent, if the treaded bushing would protrude too far, so the shaft wouldn't be long enough to retain the knob.
Did you use the original carbon element from the old controls?

[bandersen]

Got it. Thanks for the great tip

The original carbon was trashed so I had to go with new controls.

[dieseljeep]

Originally Posted by bandersen

Got it. Thanks for the great tip

The original carbon was trashed so I had to go with new controls.

According to the former post, you said that AES didn't have the proper values. That's why I was inquiring about the pots.