Restoring a 22C4113 Philco, had some questions

[Eric H]

The sharpness isn't that great because you replaced a magnetically focused tube with one that is electrically focused, you can probably improve it by applying some B+ voltage to the focus pin, it's usually the one all by itself 180 degrees from the other pins. Sometimes they focus OK with no voltage on the pin.

The centering is off because you took off the centering control, or at least the magnets. It may still work, try loosening the wing nut and slide the lever around and see if it makes any difference, regardless of the CRT type it should still work.

Removing the magnets is something that shouldn't be done, once you disassemble that focus assembly it will never work properly again even if you put the correct CRT back in, there is a polarity to the magnets and it's unlikely you would get them all back in correctly, however the centering portion may still work.

[bobwilson77]

Removing the magnets is something that shouldn't be done, once you disassemble that focus assembly it will never work properly again even if you put the correct CRT back in, there is a polarity to the magnets and it's unlikely you would get them all back in correctly, however the centering portion may still work.

Hmm... maybe I misunderstood what some others were telling me, which was to remove the permanent magnets from the assembly. On this one the magnets simply are held in place with pressure. There are 4 of them and they are are in a concave shape that fit slots shaped to accept them. Each one is for the different sides ( top, bottom, right, left). So one idea I had was maybe to try and stick one of the magnets- the right side- back into the holder to see if this would 'pull' the image to the left up front...

[Eric H]

I guess the problem her is that you don't need the focus part but do need the centering part and since they are part of the same assembly it presents a problem.

It should be possible to use a small magnet or the centering rings from a different type set to pull the picture back in line, you probably should just remove the entire focus/centering assembly so you can put the centering magnet far enough forward that it doesn't interfere with the Ion trap function.
It needs to be directly behind the yoke.

[dieseljeep]

Originally Posted by Eric H

I guess the problem her is that you don't need the focus part but do need the centering part and since they are part of the same assembly it presents a problem.

It should be possible to use a small magnet or the centering rings from a different type set to pull the picture back in line, you probably should just remove the entire focus/centering assembly so you can put the centering magnet far enough forward that it doesn't interfere with the Ion trap function.
It needs to be directly behind the yoke.

I was just wondering if a purity ring from a delta gun rectangular CRT, such as a 25xp22 would work? If the blue lateral magnet is a part of it, it would have to be removed.
Just a thought!
On some of the early sets that had an electrostatically focused CRT, they used a centering device, that was not part of the yoke cover.

[bobwilson77]

But what I'm wondering is this:
The original focus magnet assembly is directly behind the yoke. There were 4 magnets mounted in place before and they drop out whenever you loosen the back plate of the magnet assembly. If I were to re-install only the left side focus magnet, would this in effect cause the picture to shift over since at that point there would only be a magnetic pull to one side? I know that sounds incredibly goofy, but it'd basically be sticking a magnet to one side of the back of the yoke.

[Eric H]

That might work but it would be very lucky if you got exactly the right amount of shift you needed, there's also the up and down position to consider.

Centering magnets aren't very powerful, it might be possible to get a couple small hobby type magnets and pay around with them until you get it right but it might be easier to find the rear yoke cover with the rings on it already.

[bobwilson77]

I'll try that then and see what happens. And as a stupid newbie concern, if I do this I'm not risking ruining the tube am I? The magnets that came off of the focus assembly are fairly thick, chunky things. Here they are, all stuck together: