Help identify 17" CRT
 

I picked up a couple 17" CRTs today. i think both have been rebuilt. One is clearly labeled 17BP4B, but I can't find a model # on the other. As I recall, there are a bunch of 17" CRTS with similar dimensions.

Here are some pictures. The unknown CRT is about 20" long - 3/4" longer the the 17BP4B. Also, the bell seems a little larger.
Both test very good using the same settings on a Sencore CR70.

Any thoughts ?

Thanks!

http://www.bobandersen.com/images/mi...4/17BP4-02.jpg

http://www.bobandersen.com/images/mi...4/17BP4-03.jpg

http://www.bobandersen.com/images/mi...4/17BP4-04.jpg

Has it been re-gunned? Perhaps the re-builder got the seal index wrong.:scratch2:
jr

oops! you indicated that both had been rebuilt... I know of no 20" long 70 degree 17" jugs, so I am nearly convinced that the re-builder sealed the new gun on at the wrong length.

I guess I'll just see if it fits in the set. I hope it does - the emission and life test are great :)

It's kind of hard to tell from the picture. Does the right tube have a different curvature to the screen? It could be a 17QP4.

Yes, I think it has a little less curve to it. I already packed it away, but I'll pull it out again to see if it really is cylindrical. Looks like it might be from the 1st photo.

Very good point! It is difficult to tell from the photos. If it is cylindrical, it could be a 17QP4, UP4, or YP4. If it also has electrostatic focus, it could be a 17 LP4, SP4, or VP4. However, all of these cylindrical tubes are listed at the same length as the common spherical face 17"ers...19-3/16"... so I still think the length is a re-builders mistake.
jr

I lined them up face-to-face and inserted a stick between them as a reference.

If it were electrostatic focus, would there be more than 5 pins on the base ?

Here's a side view with the 17BP4 on the left and unknown on the right. The curvature is less, but I wouldn't call it cylindrical.
http://www.bobandersen.com/images/mi...4/17BP4-05.jpg

Here's a top view with the 17BP4 on the top and unknown on the bottom.
http://www.bobandersen.com/images/mi...4/17BP4-06.jpg

That is usually the case, but the 17SP4 has an internally connected focus element and only 5 pins...either way, you should be able to see the extra focus elements in the gun structure.
Nor I... but looking at my 2 Philcos with spherical faceplates, they don't look quite as flat in the vertical direction as a Trinitron did, but perhaps this is an optical illusion, caused by the Flat safety glass in front of the tube(s).

jr

Update: Just removed the safety glass on one Philco and took this shot of a cylindrical faceplate, the 17QP4 faceplate is pretty darn flat in the vertical direction.

Yeah, that sure is flat!

BTW I got these CRTs from a seller on ebay named Glenn Bubenheimer after we'd been trading emails for a few weeks. That name seemed familiar but I couldn't place it until just a few minutes ago.

When I picked up my Hallicrafters 506 in Michigan a couple years ago, the seller gave me a copy of the Detroit Free Press from 2000.
There's Glenn and his collection :D
http://farm3.static.flickr.com/2651/...be308673_b.jpg

Hey, I wondered what became of him.

He and Bryan Durbal wrote a price guide back around 1991.

Here's the gun as best as I could photograph it.
It don't think there's a focus element.
http://www.bobandersen.com/images/mi...4/17BP4-07.jpg

Sweet :thmbsp: I'll have to get a copy.

No, I don't see an extra focus element either.
Yep! I just ordered a copy.:yes:
jr

Add: here is a pix of an electrostatic focus gun... note that the second anode (supported by the white multiform rods) is in two pieces... snubbers connect the forward section to the neck dag, and a strap connects the rear section to the forward section. In the middle is a larger diameter electrode (focus) that is connected back to the base (pin 6). Focus voltage should be about 150V, but sometimes it is just connected to the first anode, or even grounded. I believe this gun is from a DuMont 14SP4.

I heard back from Glenn. He days he's been lying low for the past few years but still loves the old TVs :)


Thanks for the pix. I took a look at the free sample pages Amazon provides.
The portable I've been restoring is listed at only $25 :( On the other hand, my 20X12 is listed at $175 :thmbsp:

My copy just arrived today, other than some very slightly "dog eared" corners on the cover, it is like new! Love those 1999 prices!!!; CT100 = $500 for example :D
The pictures of the TVs are quite nice... great reference for $4.47 + shipping!
Highly recommend,
jr

Nice :) We'll have to convince Glenn and Bryan to update it. I suspect the prices have gone up a lot more for some sets than others.