5ADP31 scope tube?
 

Picked this tube up in a lot of stuff I got over the summer. I can find nothing about it. Base is the same as a 7" electrostat.

I wonder, can it be used for anything? I can't even find a basing diagram for this number.

Try this:
www.radiomuseum.org/tubes/tube_5adp7.html
P-31 is a medium persistence pale green phosphor, used in a lot of 'scope tubes, but the basing should be the same as the P-7 tube shown.

jr

IIRC the 5ADP- is a flat-faced version of the old 5CP- series.

Could make a nice CRT clock, or a spare for 60s/70s low end scopes, engine analyzers, etc..

....assuming I was talented enough to do so :)

There are several kits available if you aren't up to rolling your own...

http://oscilloscopeclocknixiecrt.com/Kit.htm

I'd probably mouse one into a 7" electrostat just for fun. I've had a few green phosphor composite monitors, and an entirely green picture makes for some interesting watching.

That shouldn't be too difficult... the tube base appears to be pin for pin compatible with a 7JP4, but one must connect the "post" connection to a positive voltage. For a "quick & dirty" it could be grounded or tied to the set's "B+", but would be brighter if a small 1-2kv module were added to the chassis. Focus and brightness controls would likely have enough range to work ok. The major difference would be the CRT deflection sensitivity which is about 3-4 times more sensitive than a 7JP4, so serious "over-scan" would occur if it was plugged into an unmodified 7JP4 set... a simple voltage divider could be added to the set's horizontal and vertical deflection circuits to remedy this.
P-31 is a pale blue-greenish-whitish color, which is suspect would be fairly watch-able, even though it may have somewhat longer persistence than P-4.
Could be the basis for *another* interesting "pre-war" replica-set. :)

jr

One weird project at a time ;). Anyone want/need the tube for the cost of shipping?