Claremont 10XP4 CRT

[bandersen]

Some of you may have seen this picture tube listed on eBay. Well, I'm the one that took a chance on it.

It arrived safe and sound although the box is in rough shape.





The only mark or label on the CRT is a "10X" written in marker.
Anyone know what this tube is ? Perhaps experimental ?



I tried testing it as a 10BP4, but had to drop the bias from -52 to -36 to get the cutoff in the black box. It test very strong and has an excellent life test.

[jr_tech]

Sure looks like an electrostatic focus gun to me, but no extra connection... focus element could be tied internally to the 1st anode (G2 in some nomenclature).
jr

[Eric H]

It sure looks like it has some Xtra parts to the gun?

[bandersen]

Originally Posted by Eric H

It sure looks like it has some Xtra parts to the gun?

It sure does. Here's a closeup of the gun.



Here's a 10BP4 for comparison.

[jr_tech]

It sure appears to have a split second anode with a short focus element between the two sections, similar to the DuMont gun that I posted on another thread:



I can't see if the focus is tied to the first anode, however.
jr

Q: How does the overall length compare two a 10BP4? It looks like the gun is pretty long.

[Eric H]

I guess the next step would be to put it in a working set and see what happens?

[bandersen]

Originally Posted by jr_tech

It sure appears to have a split second anode with a short focus element between the two sections, similar to the DuMont gun that I posted on another thread:

I can't see if the focus is tied to the first anode, however.
jr

Q: How does the overall length compare two a 10BP4? It looks like the gun is pretty long.

It's actually about 1/2 " shorter than a 10BP4.

Originally Posted by Eric H

I guess the next step would be to put it in a working set and see what happens?

Sure thing. I suppose I'll have to put the focus coil off to the side if this CRT really does have electrostatic focus.

[cbenham]

Originally Posted by bandersen

It's actually about 1/2 " shorter than a 10BP4.
Sure thing. I suppose I'll have to put the focus coil off to the side if this CRT really does have electrostatic focus.

Is it aluminized?

Cliff

[bandersen]

Originally Posted by cbenham

Is it aluminized?

Cliff

Nope, but I wish it was.

[John Marinello]

I'd try it with the focus coil in place. I didn't have to remove the focus coil
when I used the 5AXP4 in my 16GP4 Zenith.

[bandersen]

I pulled out one of my trusty Admiral chassis tonight and gave this CRT a try.

Here it is with a 10BP4 receiving a local LP VHF broadcast.


Here it is with the 10XP4 installed along with the same focus coil and dual-section ion trap magnet as the 10BP4


I think the focus coil has to go.
Luckily, I had enough slack to slide it of the CRT and put it to the side.




That definitely helped, but it was still a little fuzzy. Maybe a single section magnet would work better




Yes, definitely. Not perfect, but I have a few magnets more I can try.
Just as soon as I can remember where I put them that is

I still have no idea what this CRT is all about, but it's bright and seems to be usable

[Chris K]

Hi Bob…were you ever able to get this to work? I have the same brand, NIB CRT and I’m wondering if you made it a useable picture tube 10BP4 substitute

[bandersen]

No, I never did anything more with it. I'm pretty sure it is supposed to be a drop in replacement for a 10BP4. Could be there is something wrong with mine.

[Chris K]

I haven’t been able to get it to focus as a substitute in several focus coil TVs. Very similar smearing and soft focus you had. Same situation obviously with tested performance. It’s a magnificent tube and I tried it in my Admiral but couldn’t get it to focus with and without the focus coil. Weird

[bandersen]

Maybe it is electrostatic focus. I don't recall if it has an extra pin for focus. If it does, it needs to be connected to ground or a few 100 volts.