What is this tube ?

I have acquired a boxful of used tubes and I cannot identify what this tube is. It is a Sylvania 40A1, octal base. Anyone know what this one is? It is not listed in my RCA tube manual nor my tube tester chart.

G.

The 40A1 is a ballast/regulator tube.

Gene

Gene-
Thanks for the reply. None of my old radios use a ballast tube. So, I would probably sell this one if it is good. Anyone know how to test this ballast tube?

G.

For more info, that tube is used as a ballast tube in the cathode circuit of TV sweep tubes, such as the 6BQ6 tube. I don't know how to test it, as none of my testers have it listed.

Gene

What did the Motorola VT-71 set use? I have one of those sets and the ballast is missing...

Don, I don't have the Sams folder 55, but that is where the schematic is.

Gene

Check for continuity on pins 2 and 7, if is has continuity it is good. Emerson used these tubes in their TV's. These sell for 5-10 dollars.

Dave

Thanks Dave-
Okay I checked continuity for pins 2 to 7 and I measure 135 ohms. If this is within spec, I should probably sell this one.

G.