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

Model 70 speaker transformer wireing
#1

I am replacing the transformer on a speaker for a Philco model 70 which uses a single 47 output tube. I have the transformer. The supplied speaker is from a Model 20. I also have the Philco schematic. My question is this: I know that the two wires, from the transformer are for the voice coil. I also know that there are two terminals used on one side of the transformer and that is the primary. Opposite the two primary terminals are two which are unused. I know that they are for use as tie points for the speaker connecting cable. Here is the situation. I also need to put on a new speaker cable. From the schematic for the Model 70 it looks like I should only have three wires to the speaker plug. I suspect that one of the primary terminals goes directly to the speaker cable to connect to the 47 plate. The other secondary connects to one side of the voice coil and to another speaker cable lead which goes to supply point "C" B+ for the radio. The other field coil lead goes to point "D", which is connected to the bleeder resistor. I can easily trace the correct speaker plug connections from the chassis. However is there a correct and an incorrect way to wire the speaker field coil? While I am very experienced with radios, field coils are almost a new thing for me! Thank you.


Messages In This Thread
Model 70 speaker transformer wireing - by Tubesforme - 07-14-2016, 11:28 PM



Users browsing this thread: 5 Guest(s)
[-]
Recent Posts
identify very thin wire for replacement on 37-640
Thanks so much for your help!  I really could not have gotten this far without the kindness of you and other members.  T...georgetownjohn — 11:50 AM
Philco 38-7 Oscillation
Will do, thank you.tludka — 10:26 AM
Philco 38-7 Oscillation
As to your oscillation issue I would align the IF transformers. That may solve the problem. You also would want to check...Radioroslyn — 10:22 AM
Philco 38-7 Speaker
Thank you, I will check this out, I do have some shields I can place around the specific tubes. I searched the four que...tludka — 10:18 AM
Philco 38-7 Speaker
Also, check if any wires going to Grid Caps of the tubes that are supposed to be INSIDE of their respective shields (if ...morzh — 09:54 AM
Philco 38-7 Oscillation
Usually in this forum, when we discuss a radio, we do not multiply threads. You already have a thread on this. If you wa...morzh — 09:27 AM
identify very thin wire for replacement on 37-640
You can possibly use a heatshrink tubing. If you decide to replace the wire, anything gauge 24, 300V rated will do (it ...morzh — 09:25 AM
identify very thin wire for replacement on 37-640
Happy Thanksgiving,  I have attche a photo of a very thin wire with black plastic-looking insulation(some of it has com...georgetownjohn — 09:14 AM
Philco 60 Squealing
I got my signal tracer out to see if I could tell at what stage the squeal was coming from. It is present on the plate o...dconant — 09:07 AM
Philco 16B Parts
The 16B's in the tombstone cabinet sport a 10 1/2" spkr vs the older cathedral sets which uses an 8". The p/p ...Radioroslyn — 12:58 AM

[-]
Who's Online
There are currently 3389 online users. [Complete List]
» 2 Member(s) | 3387 Guest(s)
AvatarAvatar

>