CRT substitution reference?

[Phil Nelson]

Is there an online reference that tells you what CRTs can be substituted?

I need a couple of B/W tubes (17AP4 and 21BSP4). I know there are individual data sheets online, but you could grow old and die comparing dozens of data sheets. This question is more urgent now that nobody in the USA rebuilds picture tubes.

Phil Nelson

[leadlike]

17AP4: none

21BSP4: 21ACP4, 21AMP4, 21CUP4

So says my Howard Sams tube sub book. If your 21BSP4 crosses over to the AMP4 series though, I know it will work with just about any 21" 50s tube with that degree of deflection. I used a 21CBP4 (to replace a 21amp4A) with some very minor mods to my set (basically taking out the focus magnets as they were no longer needed, putting centering rings onto the yoke).

I think you could make any number of 70 degree 17" tubes work, but I do know that there are some differences in the face curvature of some types, so your bezel may not fit properly. My tube manual shows a few that may be able to work, but the neck lengths are different, basing is different, etc. So it wouldn't be plug and play. If I get time today, I'll check into it.

[Phil Nelson]

The Sams for my Philco F4626M lists 21ACP4A and 21AMP4A (but not 21CUP4), so I'll add 21CUP4 to my want list.

The 17AP4 in my DuMont RA-113 was replaced with a 17BP4A. The overall length is too great and the bell profile is just different enough that it's a struggle to get the yoke far enough forward to fill the screen.

It's good to know what to look for, anyhow. Thanks!

Phil Nelson

[GuyIncognito]

Check out (and download!!) this CRT cross reference I found (via a link from nostalgiaair.org's forums):

http://img341.imageshack.us/img341/9...encemanual.pdf

[Phil Nelson]

Thanks, that looks useful.

Regards,

Phil Nelson

[Tubejunke]

That manual is great, but it must be pretty early. The biggest tube is a 22" and unless I missed something there were no reference to the whole armada of 21" tubes that dominated the mid and late 1950's. Hopefully we can dig up enought data to cover stuff from the point this one leaves off up till the mid 60s, so we will have reference the 21" B&W and up to round color tubes. That will cover most of the interesting stuff. I think it is great that PDFs are available for so much old equipment and manuals that would hardly be obtainable before the WWW came along.

[Findm-Keepm]

Here's one I found from Zenith - specs, but subs can be deduced.

It's a 2.13 MB PDF:

http://www.mebeep.com/ZenithMonochrome.pdf

I can't vouch for Zenith's accuracy.....

Cheers,

[leadlike]

Phil, I checked a small repairman's pamphlet on tube subs tonight (issued by RCA in the early 70s) and it does indeed list a 17BP4 as the only sub for a 17AP4. So your tube is at least an appropriate, if somewhat ill fitting sub.

I always thought the Miss America set was a Predicta swivel screen set in a less outlandish cabinet. It's good to know that you can put a much easier to find 21" tube in those things rather than those short-lived 110 degree tubes the other Predictas take.

[Phil Nelson]

Since finding this Philco, I learned a little more about Miss America sets. Philco was a sponsor of the Miss America pageant and used that name for their top-line TVs during the 1950s (maybe later, too, but I haven't gotten that far). I found a couple of interesting ads to include in an article when I get around to writing it.

Phil Nelson

[AUdubon5425]

I have a Miss America set - has a dead 21EAP4 in it. In fact, if you see that Hyundai "retro" commercial they used in the Superbowl, the center-bottom set in the display window is a Miss America identical to mine.

[jeyurkon]

Originally Posted by AUdubon5425

I have a Miss America set - has a dead 21EAP4 in it. In fact, if you see that Hyundai "retro" commercial they used in the Superbowl, the center-bottom set in the display window is a Miss America identical to mine.

Scotty mentioned a couple of weeks ago that he has a good 21EAP4.