I restoring an old Sears Silvertone console and after getting it out of the cabinet, I took off the bottom cover...(yes, a bottom cover) and lo and behold, here's a big pile of melted transformer potting compound on the bottom.

Of course, these things didn't have fuses and the last radio I restored also had the same tell tale drippings but also a bad power transformer.

This is some pretty disgusting stuff. Looks like paraffin mixed with a bit of tar.

I powered the set up after testing for a short on the B+ line and finding none, turned the set on while plugged into a current limiter.
The set comes on with the typical loud hum but no smoke and no sagging voltages.

I'm still pretty uneasy about the transformer and am installing a three wire cord and fuse this AM but I'm thinking it might be prudent to replace the transformer like I did the last unit.

Finding a transformer that will work is no problem except for the 2.5 vac center tap winding for the type 47 audio output tubes.

So, I think there are several options and I'll list the ones I've thought of but perhaps there is another one worth looking at and .....hence, the post.

Leave the existing transformer in and lightly fuse the set. Cross fingers

Replace the transformer and add a special 2.5 v transformer for the type 47s

Series the type 47s and rectify some 6.3 and filter. Add dropping resistor or regulator to
get the 5vdc needed.

Convert the 47's to a 6v6/6f6/6k6, etc

Find a transformer with a center taped 5 vac winding and convert the rectifier to diodes and then series the two 47's and put the bias return resistor in the center tap??

Go to the tavern.

The last one seems to be the easiest but what do you guys think, what to do, what to do


Pete

Pete

Remove the rectifier and operate your radio. If the transformer doesn't overheat it most likely is good. Should only get slightly warm. Transformer can get hot enough to melt tar, from an overload, without going bad.

If you do need another transformer check here:

http://www.oldradioparts.com/2a23efl.txt

Transformers with 2.5 volt windings are near the bottom. You could also add a 2.5 volt winding on a transformer if there is room. It doesn't take many turns of wire. Many are built 4 turns per volt.

WoW!! What a find. I'll try the rectifier out tests first. I've put the site in my Bookmark

Tnx, Norm

You wouldn't believe how many radios I've gotten where the transformer has oozed disgusting crap all over the place yet turned out to be ok. Looks can be deceiving.

Last summer I had two radios, one with a very large transformer and choke can, which musta leaked out THREE CUPS of yellow wax over the years. Transformer and chokes work perfectly.