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  #1  
Old 07-06-2009, 09:08 PM
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Ampico-kid Ampico-kid is offline
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RCA Magnetic Focus Issue

I have an RCA set with a KCS47 chassis that I've been working on. This is the first set I've had where I encountered a mechanical magnetic focus system. After my initial recap and general clean up I brought the set up on a variac and it had a nice bright raster. The focus didn't look too bad, but it was very hard to adjust. There was a lot of "gunk" on the metal sleeve that slides back and forth on the neck of the crt (16GP4) to adjust the focus. I decided to remove the magnet/focus assembly and clean it. The magnets are all glued in position on one end so they were not disturbed. I cleaned it up and put it back together. BIG SURPISE.....the focus is terrible now and adjusting the control does little or nothing to help. I've tried just about everything I can think of, but the focus is quite poor now.

I saw another thread on AK regarding another set with this same issue and the solution seemed to be to remagnetize the three magnets. Problem is....the specific instructions for doing so are kind of vague and I don't have access to a high amperage 24 volt DC power source.

Just wondering if anyone else has come up against this and found a different solution? Also wondering if anyone has a spare magnet assembly I might buy and try?

The set has a great picture, it's bright and stable, but very blurry.

Attached are a few pictures of the assembly from my set.

Thanks.
Bob
Attached Images
File Type: jpg Copy of DSC_0802.JPG (120.5 KB, 24 views)
File Type: jpg Copy of DSC_0803.JPG (103.8 KB, 31 views)
File Type: jpg Copy of DSC_0804.JPG (134.2 KB, 32 views)
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  #2  
Old 07-06-2009, 09:34 PM
Don Lindsly Don Lindsly is offline
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Bob:

See if you can move all the magnets closer to the CRT neck. It looks like there's some play in the assembly.
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  #3  
Old 07-06-2009, 09:43 PM
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Eric H Eric H is offline
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I remember the consensus on these is don't take them apart, once you do they no longer work right without remagnetizing them.

I have one sitting in front of me from a 47 that I scrapped, no telling if the magnets are any better but it's yours for postage if you want it.
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Old 07-06-2009, 09:45 PM
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Ampico-kid Ampico-kid is offline
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Quote:
Originally Posted by Don Lindsly View Post
Bob:

See if you can move all the magnets closer to the CRT neck. It looks like there's some play in the assembly.
Hi Don;
If you look closely at the second picture you can see that there is a depression in the metal where the magnets sit. They are all sitting in as close to the neck as the depression allows.
Bob
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  #5  
Old 07-06-2009, 09:48 PM
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Ampico-kid Ampico-kid is offline
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Quote:
Originally Posted by Ampico-kid View Post
Hi Don;
If you look closely at the second picture you can see that there is a depression in the metal where the magnets sit. They are all sitting in as close to the neck as the depression allows.
Bob
Correction Don...it's the third picture.....
Bob
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Old 07-06-2009, 09:53 PM
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Ampico-kid Ampico-kid is offline
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Quote:
Originally Posted by Eric H View Post
I remember the consensus on these is don't take them apart, once you do they no longer work right without remagnetizing them.

I have one sitting in front of me from a 47 that I scrapped, no telling if the magnets are any better but it's yours for postage if you want it.
Hi Eric;
I wish I'd read that "consensus" before I had the urge to clean this one up. I'll take you up on your offer, I'll have nothing to lose but the cost of postage.

I'll PM you my address.

Thanks!
Bob
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Old 07-06-2009, 10:07 PM
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John Marinello John Marinello is offline
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I have a PM magnet assembly also, yours for postage, + I'll throw in the yoke.

Last edited by John Marinello; 07-06-2009 at 10:12 PM.
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  #8  
Old 07-07-2009, 09:19 AM
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Ampico-kid Ampico-kid is offline
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Quote:
Originally Posted by John Marinello View Post
I have a PM magnet assembly also, yours for postage, + I'll throw in the yoke.
Hi John;
Thanks...PM sent.
Bob
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