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New member requests help with a 38-40 ser. 121 project.
#1

Hi. I'm new to this forum, and new to radio repair.
I have what I believe is a Philco 38-40. I rescued it from a dumpster several years ago.
Aside from a few scratches, the case is in pretty good shape, and there is no apparent butchery inside.
When I first found it, I plugged it in, and nothing happened.
So, I've now read about what to do before you plug an old one in.
In spite of my (very) limited electronics experience, I intend to get this old girl running again. I think I have a grasp of what to do first, but I hope someone will correct me if I am wrong.
I intend to replace all of the capacitors (condensers, etc...) except for the mica condensers. Then, test the diode values. Then, power up with a dim bulb, or a variac (if I've found one cheap).
I'm sure that once I've gotten this far, I'll have a lot more questions.
I'm not the best at reading schematics, so does anyone have a cheat-sheet that tells me which caps I need to buy to get started?
#2

Welcome to the hobby. First I would suggest getting some good schematics and documentation on the radio. Chuck can help you with this on the Philco Test bench. Then I would do a careful evaluation on the underside of the radio, looking for anything that looks burned. Then I would resistance measure the various coils underneath. Just check for low resistance through from at least one tab to another. Then the others to one another. Just to make certain all tabs hook to at least one other. Next, I would pull the rectifier out and bring it up on a dim bulb, should not be too bright on a 60 watt. Measure the plate to plate voltage on the rectifier (A/C volt setting and on your highest scale) from the top of the socket. Should have some pretty high A/C voltage. Also measure the filament voltage from the top of the socket as well. The by now you should notice that hopefully, all the other tubes are lighting. This indicates the power transformer is probably OK.
Order up the proper caps from any of a number or sources available. If uncertain what all you have, if you go to justradios.com and give them your make and model, they will supply just what you need.
Upon receipt of the caps, just replace the electrolytics first, and test the radio. Then go slowly thereafter, a couple of wax caps at a time and test. Just the way I do it. Others will have different ideas.
I have no interest in the vendors suggested other than they work for me. Good luck.
Jerry

A friend in need is a pest!  Bill Slee ca 1970.
#3

Interesting set as it can be operated from 115vac or 6vdc.
Terry

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




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