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Kevin Kuehn 11-30-2012 03:17 PM

Quote:

Originally Posted by IsthmusTV (Post 3055446)
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 11-30-2012 04:02 PM

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 11-30-2012 04:18 PM

Quote:

Originally Posted by Phil Nelson (Post 3055451)
... 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 :thmbsp: I need to take the set apart again and dig it out :sigh:

bandersen 11-30-2012 05:59 PM

I found it :)
http://farm9.staticflickr.com/8065/8...8f98bbe0_c.jpg

That's better :yes: Thanks for the quick help guys :D
http://farm9.staticflickr.com/8341/8...c4492ea7_c.jpg

Eric H 11-30-2012 06:35 PM

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 11-30-2012 06:56 PM

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. :D

bandersen 11-30-2012 08:26 PM

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 11-30-2012 09:24 PM

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

Phil Nelson

bandersen 11-30-2012 10:00 PM

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 11-30-2012 11:13 PM

Great video.

dieseljeep 12-01-2012 10:20 AM

Quote:

Originally Posted by bandersen (Post 3055006)
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
http://www.tubesandmore.com/sites/de.../r-v100k-n.png

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. :D

bandersen 12-14-2012 02:07 PM

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.
http://farm9.staticflickr.com/8197/8...daacfe48_c.jpg

A Dremel tool and cutoff wheel took care of that.
http://farm9.staticflickr.com/8338/8...9b7de604_c.jpg

Much better :yes:
http://farm9.staticflickr.com/8208/8...6291b986_c.jpg

dieseljeep 12-14-2012 07:05 PM

Quote:

Originally Posted by bandersen (Post 3056608)
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.
http://farm9.staticflickr.com/8197/8...daacfe48_c.jpg

A Dremel tool and cutoff wheel took care of that.
http://farm9.staticflickr.com/8338/8...9b7de604_c.jpg

Much better :yes:
http://farm9.staticflickr.com/8208/8...6291b986_c.jpg

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 12-14-2012 09:36 PM

Got it. Thanks for the great tip :thmbsp:

The original carbon was trashed so I had to go with new controls.
http://farm9.staticflickr.com/8480/8...05244970_z.jpg

dieseljeep 12-15-2012 09:40 AM

Quote:

Originally Posted by bandersen (Post 3056646)
Got it. Thanks for the great tip :thmbsp:

The original carbon was trashed so I had to go with new controls.
http://farm9.staticflickr.com/8480/8...05244970_z.jpg

According to the former post, you said that AES didn't have the proper values. That's why I was inquiring about the pots. :scratch2:


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