Thanks, Ron. By coincidence I ran into a co-worker who is also a tubehead and had a technical conversation about many things, including this.
However, he was trying to convince me to put the chassis as it is on the variac, and ramp it up nice and slow... I think I'll still execute a thorough survey of the undercarriage before I do that. He also agreed that it would behoove me to put a polarized plug on the chassis for the purpose of putting a fuse into the hot side of the line. (If I'm putting all that work into restarting the radio, I might as well protect it, yes?)
I am finally working on this radio, and today I experienced a Philco Rite of Passage: My first tar-boat.
It went well, at least so far. I have all the crud cleaned out of the boat and have cleaned it with mineral spirits to remove the last of the goo. Now, to install the new capacitors... here's hoping I remember how to read a schematic. Thank heavens for landmarks like a power switch!
Oh, bugger... just checking--if a capacitor isn't marked with a polarity, it doesn't have one, right?
If it is not an electrolytic, a capacitor has no polarity. Disregard the bands on old wax capacitors (indicated outside foil.) Modern capacitors have no such designation. Always double check schematic for value, as some capacitors are not clearly marked.
D**n and blast! Things were going well until I was trying to un-solder a connection and broke my 6J8G tube socket. Any suggestions where to get a replacement?
Or alternatively, I do have the piece I broke out (it's the one retaining the pin socket, natch).
Is it reasonable to even attempt to repair the socket with a couple of dabs of superglue and prayer?
Superglue, no. Two-part clear epoxy, maybe. (EDIT: I should have been paying closer attention...or I shouldn't post after driving all afternoon and part of the evening. You are referring to the center key, correct? Forget about it. Replace the socket.)
Your 6J8 socket is sort of tan in color, compared to the dark brown of your other sockets, yes? I ran into the same problem with two of the tube sockets in my 41-616. That tannish color material Philco used to make some of their sockets during 1940-41 is very prone to breakage. The brown wafer sockets are much, much better than those.
The lighter tan socket is indeed the culprit, and I thought it looked lower in quality.
Actually, the keyhole survived. It's the little chunk of bar that holds the #6 pin in place. A closer inspection reveals that the socket has warped slightly and allowed almost all the pin sockets to come loose, so I suspect replacing the socket is overall a better idea for future generations (or even in a couple of weeks when I try to put the tube back).
Where the heck do I get a replacement socket? I looked around on line and found loads of loctals and large-pin 8's, but I couldn't find a small-pin 8 anywhere (it doesn't help that sellers seldom include a flat picture of the socket so you can actually get a good look at the pin configuration).
Do what I do...use a brown wafer socket from a junk Philco set of the same era. It will have the extra benefit of matching the other sockets in appearance.
I don't know this to be fact, but I suspect the tan sockets were some sort of low-loss material made for use with detector-oscillator tubes. The brown wafer sockets work just as well. I really don't know what they were thinking when they came up with those tan sockets. Obviously, they didn't suspect that people like us would be collecting, restoring, and using these radios 72 years on.
Quote:Obviously, they didn't suspect that people like us would be collecting, restoring, and using these radios 72 years on.
Word.
On this front, I tried the two-part epoxy (JB Kwik to be precise) and the pin socket that has been resecured with the narrow band of tan material is now stronger and more stable than it was prior to surgery. I'll see how it goes once I subject it to 40 watts of soldering iron.
Well, if it does not well, I or someone else will gladly contribute a ceramic socket to replace. You're going to be quick and fast to do a solder joint. Of course remove the tube. Like have everything ready and make a good mechanical connection first maybe use a little rosin flux and zoom in with freshly tinned and blobbed and hot iron and zap some narrow guage 60/40 or better and leave it cool for a while. You don't usually get a re-do on these things.
Post the chassis hole size and riveit spacing and orientation of pins if you need a spare socket. One of us will give you one.
I may have managed a repair.
Two pieces went to the tab, so I J-hooked them to a single lead (less to heat at the connection) and off we went... the epoxy started to bubble but I got the single lead soldered onto the tab and now I'm letting everything cool (including myself) before going onward.
And a short while later, while trying to solder on a lead extension, burned my finger on the soldering iron. Net result: done for the day. Make notes on where I was in the process, clip a few color-coded test leads to "*this* goes to *this*" and start the ibuprofen (and possibly beer).
Whine.
Tried again this afternoon and inadvertently melted the wax of the RF coupling transformer (part #1 on the diagram). Any suggestions? Can it be re-coated?
Either way, I'm done for today as it's clearly not meant to happen.
Well, if you didn't burn out the winding on the coil, I'd leave it alone or possibly dreip a little wax from a beeswax candle if it tests OK. (Ask the old lady for one.)
I still don't think trying to repair an old tube socket is wise, no matter what.
Take a few days off, go fishing, or something, and come back.
Agree with Codefox on this one. Take a little time off from this project, and when you return to it, check the continuity of that coil first thing.
(after looking at schematic)
Wait a minute. (1) is the set's loop antenna. Do you mean (13)? That is actually the RF coupling coil. In any event, check for continuity before proceeding.