Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Philco Model 37-38B Questions
#8

For testing purposes what you could do is use the opt as is. Since the stage uses triode sections of the opt tube there is no issues with damaging the screen grid thru over dissipation. There will be a slight drop in output about 15% but 19 is a pretty stout tube.

This holds true for triode connected tetrodes or pentodes. Like the Philco Super Class A output stage (P/P 42's w/the screen grid connected the plate). Bob and I did it on a 116B w/a 1/2 open opt. 

What you don't want to do is is operate a set w/1/2 an opt and tetrodes or pentodes that the screen grid are connect back to hv line. In this configuration there is no plate voltage on the plate. So, the screen acts as the plate would but it can't dissipate the current that the plate can. In some cases, the screen will light up and burn up and tube's gain drops to 0. I think I hear Chopin playing in the background.    (No Copyright Music) Funeral March (by Chopin) by Chopin - YouTube

File this under cheap tricks. [Image: https://philcoradio.com/phorum/images/sm...on_lol.gif]

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry


Messages In This Thread
Philco Model 37-38B Questions - by jjfritz5528 - 10-14-2023, 12:32 PM
RE: Philco Model 37-38B Questions - by morzh - 10-14-2023, 01:33 PM
RE: Philco Model 37-38B Questions - by radiorich - 10-14-2023, 01:49 PM
RE: Philco Model 37-38B Questions - by morzh - 10-14-2023, 03:51 PM
RE: Philco Model 37-38B Questions - by morzh - 10-19-2023, 08:31 PM
RE: Philco Model 37-38B Questions - by Radioroslyn - 10-20-2023, 09:27 AM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco newbie with P-1891-WA console questions
Well, I've been stumped at trying to get the first of 11 electrolytic capacitors. I got a schematic and have a list of t...Jeffcon — 07:54 PM
Model 80 Antenna Issue?
Thanks Gary and Rod.  I also found an article in the Philco Repair Bench under Service Hints and Tips, about installi...Hamilton — 12:32 PM
Model 80 Antenna Issue?
Hello Hamilton, here is a little information found in our Philco Radio Library at the bottom of the Home page. Hope it ...GarySP — 11:28 AM
Model 80 Antenna Issue?
I did as you suggested and touching the middle of the volume control did nothing so the coil has to be rewound. Any idea...Hamilton — 10:19 AM
1949 Motorola 5A9M
This would be the second portable in the "other radios" forum where I have a similar one in my collection. I h...Arran — 12:41 AM
Looking for any info: 1977 Ford-Philco Console Hi-Fi Turntable and Radio
Hi PittsburgTost. The record changer looks like a Garrard or BSR (Likely Garrard). The spindles just pull out and pu...MrFixr55 — 11:57 PM
Looking for any info: 1977 Ford-Philco Console Hi-Fi Turntable and Radio
Hello PittsburghToast , Welcome aboard and it looks like gary may have something for you ! now if I dig through my se...radiorich — 11:35 PM
Model 80 Antenna Issue?
You are kind of on the right path. You can touch the grid cap of the Detector/Oscillator 36 tube. I'm expecting a respon...RodB — 08:48 PM
Looking for any info: 1977 Ford-Philco Console Hi-Fi Turntable and Radio
Welcome to the Phorum, PittsburghToast!  I found an old thread that my interest you regarding the quality and worth of P...GarySP — 08:48 PM
Looking for any info: 1977 Ford-Philco Console Hi-Fi Turntable and Radio
Welcome to the Phorum! :wave: We do not have anything on that unit in our digital library. There is a Sam's Photof...klondike98 — 08:47 PM

[-]
Who's Online
There are currently 1073 online users. [Complete List]
» 1 Member(s) | 1072 Guest(s)
Avatar

>