Substitute CRT: http://cgi.ebay.com/Vintage-CRT-Substituter-Round-TV-Picture-Tube-Tester-/190475251839?pt=Vintage_Electronics_R2&hash=item2c5935b07f

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Not at that price!

Those 5AXP4 tubes are very useful but they can be had for $20 without the fancy box.

I picked up the exact same model on epay for $18 plus. They are handy - but not $300 handy!

I picked up one a few months ago for less than $10.
Mine was not as nice as that one and the rubber bezel was broken and crumbling.
I removed the 5AXP4 from the box and use it without the test box.

Makes a nice test CRT.

Carl

I've got one; handy for use with sets that mount the crt/yoke to the cabinet, like a couple Philcos I have. Don't connect the yoke connections tight enough and you can burn a dandy hole in the phosphor! Nice orange glow...ouch!

Picked mine up at an antique store, seller thought it was some sort of flashlight! I think I paid $10 or $15.

Here's a well used 5AXP4 a bit more reasonably priced: http://cgi.ebay.com/5-inch-round-70-deg-Monochrome-picture-tube-vintage-/230563725755

Doesn't the B&K TV analysist use the same tube for the spot scanner?

Nope. It looks similar, but is actually an ultraviolet CRT

Hey, this is what I kept mentioning needing in my Zenith Space Command post. To me, this thing essential in the repair of a set that was not designed to have the crt come out with the chassis, and there were a lot of them. If anybody gets a lead on one please let me know. I saw the post about a "well used" tube, but if I get one I want to get a good one. This would help me tremendously!

Well, it doesn't mean it's bad. The one I got off eBay looks just as worn and scratched, but works fine. They're pretty hard to kill.

This would help me tremendously!
Note that there are different kinds of test tubes, and any given one will not necessarily substitute for every other tube ever made. Here's a website where you can look up tube data sheets:

http://tubedata.tigahost.com/tubedata/

The data sheets will show the pinouts, deflection angles, etc., for both tubes, and thus you can tell whether test tube X can substitute for tube Y.

Phil Nelson

The 5AXP4 will sub for most late 40's round B&W tubes like the 10BP4, 12LP4, 12QP4, 12JP4 etc, it will NOT sub for a mid 50's 21" tube however, the HV is too much for it to handle, it arcs inside, I know this for sure... somehow... :rolleyes:

The large neck rectangular tube is an 8YP4 or an 8XP4, can't remember which is which, they will work for the big rectangular tubes.

I don't get it really, because the neck diameter and socket footprint is the same for a 1947 10BP4 as it would be for a 1956 21ZP4 or my 1958 24AJP4. I can understand the problem with high voltage arching. Perhaps there was a procedure or special connector to control second anode input to the tube. Anyway, if anyone spots one that is suitable for my 24AJP4, please drop me a line. Thanks!

The 8XP4 is the rectangular version. Max 22 kV: http://tubedata.tigahost.com/tubedata/sheets/168/8/8XP4.pdf

5AXP4 is round. Max 18kV: http://tubedata.tigahost.com/tubedata/sheets/168/5/5AXP4.pdf

The rectangular 8XP4 will work in round CRT sets, but the deflection angle is different so the image will be clipped or distorted.
http://farm5.static.flickr.com/4075/4921096267_ded3ffc4d8.jpg

It's not just the high voltage, the geometry difference between the round tube and the rectangular would prevent it from displaying a picture correctly.

The rectangular tube will work in a round set but it's useless for setting it up.

Edit: Phil beat me to it by two minutes!

Yes, I would imagine that it is simply for someone like me trying to check voltages on one of these non chassis mount crt sets. You would just need to see the basics as far as sweep, brightness, sync, etc. Definitly no way to set up picture...

Here's what they look like side by side. Left to right we have the 8YP4, 8XP4 and 5AXP4.
http://farm6.static.flickr.com/5122/5265804644_ba2de0c3ae_z.jpg

Bob,
Boy, that Rauland box sure triggered a lot of old memories lost up there in my cranial cobwebs.

Wow! That on the left is interesting. A lot of my vintage test equipment and NRI stuff came from a pile of stuff that a friend found on the curb after an old repairman died and his wife decided to sweep his memories to the dump. Anyway, out of all of the stuff that I did get, I DIDN'T get a bunch of maybe 4" round crts with a grid of some sort on the face. The socket and neck seemed to be the same size as any 40s-50s tube. I thought that they would just be more useless stuff taking up space, but now I wonder if some museum might be interested in them. They are still there as far as I know. The one in your picture looks like the neck is much smaller than the others.

Bob,
Boy, that Rauland box sure triggered a lot of old memories lost up there in my cranial cobwebs.

I was very happy to get the original box and paperwork. I didn't look like it had ever been used.

Wow! That on the left is interesting. A lot of my vintage test equipment and NRI stuff came from a pile of stuff that a friend found on the curb after an old repairman died and his wife decided to sweep his memories to the dump. Anyway, out of all of the stuff that I did get, I DIDN'T get a bunch of maybe 4" round crts with a grid of some sort on the face. The socket and neck seemed to be the same size as any 40s-50s tube. I thought that they would just be more useless stuff taking up space, but now I wonder if some museum might be interested in them. They are still there as far as I know. The one in your picture looks like the neck is much smaller than the others.

I've seen a number of 8YP4s with a grid on them. Mine uses a tight fitting plastic film with the GE logo in one corner.
Yes, the neck is the smaller type used on newer, more rounded B&W CRTs.

http://farm6.static.flickr.com/5247/5267833646_13d5eb7cea_z.jpg