[qanerd]

I recently acquired a mostly unmessed-with and completely unrestored 37-116. It's in pretty nice shape, not missing too much, and I want to do a correct restoration. I have tried to read as many posts as I could before posting this. I am going to probably have a million question but I will start with just a few:
There is a tube in my chassis labeled 6H6 (Sylvania). Obviously a replacement as the tube layout calls a 6H6G. The original 6H6G is an octal double diode. The 6H6 is a squatty little black tube with no glass envelope, no shield (although the socket has provisions for one) and it does NOT want to come out. I am a little afraid to reef on it. Soooo, is this an acceptable tube for this socket (I would assume it would work with that number), does it need a shield and am I missing something trying to get this thing outta there? I've attached a picture.
Thanks in advance for your help
Chris G

[codefox1]

The sub is good. I've newer seen a 6H6 glass tube, but either one will work. You may have to spray a little deoxit or WD40 from underneath the chassis on the socket, and gently pry this tube out with 2 screwdrivers at the same time on opposite sides. Eventually you will get it out. But then again, these seldom fail, so after the recapping, etc... you might be good to go.

[John R]

Chris,
Make sure that if you decide to use the metal 6H6 detector tube that pin 1 on the tubes' socket is used only for a ground connection and not a tie point for other circuitry. The metal envelope of metal encased tubes act as the shield and their pin 1 is normally tied internally to the metal shield therefore pin 1 on the socket should be ground. On glass envelope tubes such as a 6H6G or 6H6GT pin one may not have been ground but used as a chassis tie point for other components. Glass tubes as you can see often use external metal shields to suppress oscillations and intermodulation effects, etc. Hopefully, whoever changed this tube out looked at this aspect? To my knowledge Philco did not use metal
tubes prior to WWII? If you decide to restore this set to original you may want to install a glass 6H6GT and find a metal shield...it's up to you of course. Glass 6H6GT tubes are not expensive and may be found from many suppliers.
Best wishes on you radio restore. John

[qanerd]

John
Thanks for the advice. I am inclined to use the 6H6G with a shield as it is period correct.
Regards
Chris

[Arran]

The original tube was likely a 6H6G type, sometimes also called shouldered tubes, but I suspect that they are somewhat harder to find then a 6H6 GT. The 6H6 is a dual diode with no grid cap lead to deal with, and uses a normal Philco tube shield, so you can stick whatever glass tube you like in it's place, a metal tube just looks wrong in there. If it used a Goat type form fitting shied you would want to find a 6H6 G with an ST style glass.
Regards
Arran

[codefox1]

Whatever you find and adapt, a couple of simple diodes could do the legwork. My god, it was about 40 years ago on training can. USNR.