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 20 Speaker Plug Question
#2

Hi and welcome to the Phorum.

Ok so what we need to do is find the center tap on the primary of the output transformer. That connects to one side of the field coil. In turn it go to #27 the choke in the HV side of the power supply. The other field coil lead goes to the primary of the interstage audio transformer and the bottom end of #18 the 1/4meg resistor. The two ends of the primary connect each plate of the 71A tubes.

Piece of cake!
https://philcoradio.com/library/images/schem/20b.jpg

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 20 Speaker Plug Question - by Mwryute1 - 10-26-2022, 07:18 PM
RE: Philco 20 Speaker Plug Question - by Radioroslyn - 10-26-2022, 10:27 PM
RE: Philco 20 Speaker Plug Question - by Mwryute1 - 10-27-2022, 12:56 PM
RE: Philco 20 Speaker Plug Question - by Mwryute1 - 10-27-2022, 01:07 PM
RE: Philco 20 Speaker Plug Question - by MrFixr55 - 10-27-2022, 02:31 PM
RE: Philco 20 Speaker Plug Question - by Mwryute1 - 10-28-2022, 03:35 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Zenith H725
David - I think I understand but what units are you discussing (Low of 1.7, high of 3.9)? Budget constraints for Ham ...EdHolland — 01:43 PM
My Philco 37-116 Restore
You're doing great. I wish I could be more involved, but my mind is right now preoccupied with the reason I am here in ...morzh — 12:21 PM
My Philco 37-116 Restore
Hope you guys are still with me. I have moved on to the alignment. I completed the IF alignment which was pretty muc...dconant — 10:47 AM
My Philco 37-116 Restore
Hello MrFixr55, Thank you for taking the time to explain. I measured 50 volts where you say. Today the 370 volts at ...dconant — 12:51 PM
462ron
Oh that sucks. It’s something easily overlooked. Hopefully it’s nothing more than a resistor! Ron462ron — 08:08 AM
Philco 46-480 Electronic Restoration
Just confirmed that you are correct. It’s the function generator. I connected the signal output probe to one of the inpu...jrblasde — 07:52 AM
Philco 46-480 Electronic Restoration
Ouch, you may be right. Yes, it is solid state. It’s the signal output of my oscilloscope. May be time to crack that ...jrblasde — 07:27 AM
462ron
If you didn’t put a DC blocking cap between the signal generator probe and the plate of the 1st IF it’s possible you ble...462ron — 07:07 AM
My Philco 37-116 Restore
Hi DConnant, The reason why C127 is isolated from ground is because sets of this vintage did not have the center tap...MrFixr55 — 01:07 AM
Philco 46-480 Electronic Restoration
The shield is on the 6H6. It was, in fact, a missing jumper to connect the main chassis ground to the RF chassis grou...jrblasde — 10:58 PM

[-]
Who's Online
There are currently 1107 online users. [Complete List]
» 3 Member(s) | 1104 Guest(s)
AvatarAvatarAvatar

>