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THE AM BULLETIN BOARD => Technical Forum => Topic started by: WU2D on January 10, 2010, 05:16:17 PM



Title: How Good is Your TUBOLOGY?
Post by: WU2D on January 10, 2010, 05:16:17 PM
I got a call from an OT who is in my Lions club and he apparently was a ham at one time. He told me to remove these nasty tubes from his basement. I selected a few from the pile for your enjoyment.

Here is a line up of nice valves from the cache for you guys to identify - Who can identify the lineup from left to right? Let's hear the guesses ???....

Mike WU2D


Title: Re: How Good is Your TUBOLOGY?
Post by: w8khk on January 10, 2010, 06:07:32 PM
I'll take a shot at your quiz...

1   807   HF beam power tube (pentode)
2   2E26  VHF beam power tube (pentode)
3   I don't have a clue, but it looks like an old gaseous VR tube
4   316A  UHF triode
5   705A (VT255) half wave rectifier
6   826 VHF triode


Title: Re: How Good is Your TUBOLOGY?
Post by: WU2D on January 10, 2010, 08:14:12 PM
Good Job Rich,

You have 4 of them so far...

Any more guesses?

Mike WU2D


Title: Re: How Good is Your TUBOLOGY?
Post by: WU2D on January 10, 2010, 10:09:24 PM
OK Here they are:

1. The 807 Pentode - Everybody should have gotten that one! You could see that it was not a 1625 by looking at the pins.

2. 2E26 Pentode - pretty distinctive - easy one.


3. 3B22 \ EL1C  Full Wave Xenon Rectifier - a little harder

4. 368AS (or 703A) UHF Door Knob Triode

There are 2 kinds of door knobs the 316A and 388A larger types and the 368A (S) or 703A smaller types. This is the 368 or JAN-368AS by Tung-Sol. It is a door-knob shaped UHF transmitting triode, single ended, usable as oscillator up to 1400MHz. 20W anode dissipation. Also known as 703A.
Made by WE and STC. The larger Door-knob tubes such as the 316A were more plentiful and popular.

Note the offset nipple on the 368AS. The 316A has the nipple in the center.

5. 705A (VT255) half wave rectifier 35 kV PIV, 100 mA AVG, 500 mA Max Peak, 5.0V 5A Fil

6. 826 VHF triode - transmitting tube 55 watts plate dissipation class C with plate modulation about 70 watts out. 7.5V/4A filament, 1kV/125mA operating.

Except for the 807 and 2E26, I knew little or nothing of these tubes!

Mike WU2D


Title: Re: How Good is Your TUBOLOGY?
Post by: w8khk on January 11, 2010, 03:12:32 PM
Thanks for sharing the tube pics and info, Mike.

If I recall correctly, the 316A was used in the BC-645 WWII IFF transponder.  It did have the nipple in the center of the top, and the hold-down hardware was centered about the nipple in that rig.  Back in the 50s we had a couple units, but never got around to conversion for ham use.  I see now that the 368AS is much smaller than the 316A/VT191.  I should have done a bit more research before posting, I just shot from the hip and answered from memory. 

Would be neat to see a few more tubes from your new stash!
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