If you can figure out the pin-out, that would narrow it down considerably. Then measure the heater current at 6.3 V (assuming that lights it up properly).
We are left with the hammer option. Or destructive testing. (where's Tubelab)
Triode or Pentode?
How many Watts will it take before bursting into flames?
Time to call in the experts:
Triode or Pentode?
How many Watts will it take before bursting into flames?
Time to call in the experts:
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I have been known to "test" mystery tubes.....usually not destructively. I prefer the term "boundary testing." I find the glow point and back up a bit. Before any testing can be done, the pinout must be determined. The plate is obvious, and the heater should be fairly easy to figure out. The rest should be possible with careful examination.
7403 has an odd pinout, but an easy test. Heater is on pins 1 and 2. Tung Sol did make them, and the square plate looks about right.
The OP had previously stated that he had some 7403's, so some comparisons should be in order.
I thought the 7403/3D21 had ceramic insulators. Looks more like mica in the posted pic. Also not sure if the plate cap is matching. With the bakelite base it probably does not dissipate as many Watts as the 7403. (Tungsol 7403 pic below, then mystery tube)
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None of my 6146/6883 look like that. The side mica "wing" on these is not there on 6146 tubes I've seen.
Diameter of the glass body would help.
Diameter of the glass body would help.
I have a bunch of 6293 and most look like a normal 6146; a few like a 7212.
The mystery tube looks like something from the 59XX series.
WAG - some ruggedized 2E26 type for aviation.
Win W5JAG
The mystery tube looks like something from the 59XX series.
WAG - some ruggedized 2E26 type for aviation.
Win W5JAG
The boxy looking plate looks a lot like that of a Tung-Sol manufactured 5931 (6L6WGA) I have, what about identifying the heater connections, and assuming the glow looks normal, measure the heater current at 6.3 volts - if it's remotely related to the 6L6 family, it will draw ~0.9A.
On the pinout...look inside and make what guesses you can. Test with a tester where the g1, g2 and cathode are labeled...and try some combinations until you find the connections. Look up that base connections in the RCA handbook, then go to TDSL and look for tubes with that basing...then a google images search through the vacuum tube museum should get you the answer...🙂
cheers,
Douglas
cheers,
Douglas
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