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

511 series AF transformers
#1

After replacing a burned out 71A tube I was getting one strong channel but no volume control. I figured I'd recap it and see what I got. While waiting for the new caps to arrive I went through the chassis more thoroughly and found that the output choke was taken out of the circuit with the speaker connected directly to the 71A and worse, the 2 AF transformers (#3077) appear to be open... I doubt I'll be able to find replacements and I don't want to put a lot of money into it. Is it possible to rewind these myself or use some modern replacements?
#2

Hi

While these can be rewound, modern replacements are available for the audio interstage transformers from a few sources. You will want transformers with a 1:3 ratio.

Or, you could change the audio interstage transformers to resistance coupling. Details here:
http://www.philcoradio.com/tech/audio.htm
Scroll down to "Modification C."

--
Ron Ramirez
Ferdinand IN
#3

Thanks Ron, I will try the resistance coupling if I can't find an appropriate match. This may be a silly question but, could I use a 110v to 36v power transformer (1:3 ratio) as a substitute? Also what kind of current rating should be used?




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Hickok AC51 tube tester
I think they have only shown the secondaries of the transformer. Two of them feed the rectifiers' filaments.morzh — 12:58 PM
IF can wire size and Rubber mounts?
Arran If the wire inside cans is the gauges you mentioned, the sole reason for that would be mechanical, to stiffen t...morzh — 12:56 PM
12' Philco
Rod, Yes, I know, but the Giant Philco is not around anymore either, so I go by whoever was alive fairly recently. H...morzh — 12:54 PM
Hickok AC51 tube tester
Absolutely no one is going to reverse engineer that circuit. Even the iron core is missing.RodB — 10:37 AM
IF can wire size and Rubber mounts?
Thanks to both members for your help regarding wire and tuner mtg supports. regards--Johngeorgetownjohn — 09:33 AM
Hickok AC51 tube tester
Note that no power cord, power switch, or power transformer switch are shown. That (along with my experience with full s...DaleHCook — 07:09 AM
IF can wire size and Rubber mounts?
A pair of wire strippers can give you an idea of what the existing gauge of the wire leads are in the IF can, I think it...Arran — 06:07 AM
My last cabinet for this year
Hello Dan, That is really beautiful what great looking radio you have ! I have friends who live in Calgary and the wea...radiorich — 01:51 AM
Philco Predicta Siesta picture over time getting dimmer
I found that the wire insulation was burnt.  The fly back needs corona dope! Why would someone put that there?Platinumblonde36 — 01:09 AM
Philco Predicta Siesta picture over time getting dimmer
This is what it looked like beforePlatinumblonde36 — 01:01 AM

[-]
Who's Online
There are currently no members online.

>