Zenith 2250R

[Electronic M]

The trap position varies from tube to tube. One trick is to take the trap off and flip it around such that the opening that faces the socket instead faces the screen.

Common position is close to the socket, but I have seen them mounted all over the neck.

[Kevin Kuehn]

I suppose it's possible someone replace the ion trap with the wrong type. There are double and single magnet types. I would guess any 12" CRT from that time would use the double magnet? It usually specifies in the CRT type specs.

[Zsuttle]

Originally Posted by Kevin Kuehn

I suppose it's possible someone replace the ion trap with the wrong type. There are double and single magnet types. I would guess any 12" CRT from that time would use the double magnet? It usually specifies in the CRT type specs.

I’ll have to try it, the screen does have a little burn in in on the front of the tube from prior usage. The data sheets mentioned a single field ion trap, I’m assuming that means a single magnet ion trap.

Interestingly, the one shown in the service manual is different than the one that was on the tube.

[Kevin Kuehn]

Originally Posted by Zsuttle

The data sheets mentioned a single field ion trap, I’m assuming that means a single magnet ion trap.

Actually there's quite a few with a single magnet on the side that have two sets of bars extending to clamp around the neck. If I'm not mistaken those would qualify as a double field. I'll see if I can find textbook examples of the two types. Can you see the type number on the neck of the CRT in your TV?

[dieseljeep]

Originally Posted by Kevin Kuehn

Actually there's quite a few with a single magnet on the side that have two sets of bars extending to clamp around the neck. If I'm not mistaken those would qualify as a double field. I'll see if I can find textbook examples of the two types. Can you see the type number on the neck of the CRT in your TV?

Looking through the pictures, it looks like a 12UP4 metal cone CRT.

[Kevin Kuehn]

Originally Posted by dieseljeep

Looking through the pictures, it looks like a 12UP4 metal cone CRT.

I can't tell. All the pictures seem to be from the front and the green Zenith mask is covering the edges of the CRT.

[dieseljeep]

Originally Posted by Kevin Kuehn

I can't tell. All the pictures seem to be from the front and the green Zenith mask is covering the edges of the CRT.

Every 12" Zenith I've seen used a metal cone CRT! The 10" model used a 10BP4 glass tube.
It's been probably 50 years since I worked on one of those.
The Sams would probably show the top view of the chassis and the CRT.