[bm071]

If I am comprehending all of this correctly...when I started working on this chassis it would not play, this transformer was already replaced, and I found one of those resistors was missing. I beleive it was #110 or 115 on the schematic.  It's been at least three years since I've done the work so I cannot remember exactly. ..  I put a post on the for sale board asking for one of these. Hopefully someone has a junker willing to sell. If Mike has a solution great but I would need step by step guidence to fix. Sorry!!  I do appreciate all of you taking time to help.. Thank You all!!!

[morzh]

I found you the transformer, in your post in Want to buy I left you the links.

[SteveJB]

See if this is what you need. I tried a PM, but I cant tell if it is going trouugh so I am reposting here.

This is what I measured (all from chassis ground):
from the plate of the 6J5 driver it is 256 vdc
From the positive side of e-cap 70B it is 256 vdc.
 
Then I had my chassis upside down in a cradle with the transformer on the bottom. Looking at the 6 pins, there are three vertically on the left side and 3 vertically on the right side.
I get the following starting top left, then middle, then bottom left:
-21 vdc
-21 vdc
-21 vdc
 
On the right side, I get top, middle and bottom:
-21 vdc
256 vdc
256 vdc
 
My set read about 20-30 volts low on all the tubes, but it plays well.  I don't know old the same holds true here.
 
Here is a picture from the bottom as I described it above (the trans is between the bakelite bock and the 6J5 Driver tube socket:
http://i1033.photobucket.com/albums/a414...uhj9nw.jpg

[bm071]

Just wanted to say thanks to Chuck at the Philco Repair Bench. With his help and a little after market vintage tech info  Heyboer will be able to re-produce this step down input transformer. It should turn out to be a real close or same  match of the original.   If anyone is in need I will have a part number/specs etc. ...soon.  


Thank you everyone!!!!

Bob

[klondike98]

I merged this with the original thread.

[Diverted]

Just curious: Why is there seemingly such a high failure rate on the interstage transformers in these high end '38 sets? I just bought a 38-690 and the primary on my interstage is open; I have since heard of others with the exact same problem, and now with the 116 as well. I'm having mine rewound by Heyboer; they've done several (part 32-7876n).

Ted

[Mondial]

Its not just the high end sets. Audio interstage and driver transformers are a common failure item in general. They are wound with many turns of fine wire and the wire has a tendency to corrode away, especially at the terminations to the leads or terminals. 

A lot has to do with the flux used in soldering the fine magnet wire to the terminations. If it is acidic and the radio is kept in a damp place, the resulting corrosion just eats the very thin wire away.

Sometimes there must be a very bad batch of flux. I have a model 20 chassis otherwise in very nice condition where every transformer and choke has at least one open winding, or has already been replaced. On the other hand, I have another identical chassis where every transformer is original and in perfect condition, so it must be something more than just random failure.

[morzh]

So was my 66 and most of 111. Corrosion. Green broken wire.

[Diverted]

Oh well, it is what it is. It'll make it sound that much sweeter once I fire it up for the first time.