The Philco 41-231 Still Sings Beautifully! (almost)
 

It's hard to believe that I got this wonderful Philco almost a year ago. I got it for free off a friend. It only got two stations when I got it. Easy fix, all I had to do was solder the antenna cable back together. Does anybody here attend the annual Michagan Antique Radio Extravaganza? I will not be able because I was forced to be in high school band, and they have some stupid camp that I must attend that week. :dammit: What is probably most incredible about this radio is that it has ALL the ORIGNINAL wiring, capacitors, transformers, everything is original. Unfortunately, it is slowly developing symptoms related to bad paper capacitors and electrolytics. There might be a recapping session for this radio in the near future.:worried: I have no idea how to recapp a radio. I dabbled with recapping 70's Sony and it did not go so well...

Nice looking radio.

UPDATE: I talked to the band director today, and he said that he might be able to work something out for me!

Your radio is probably from the era of the Philco rubber wire insulation. It really makes restoration tricky, at best.
According to the schematic, there's a lot of paper caps in it.
Interesting design, using the dual triode convertor tube and two stages of IF. Not your usual AA6. :thmbsp:

Philco is one of the best radios to work on, IMHO.
For yours to work like that, I'd bet that the electrolytics were replaced, even 50 years ago.
If you're concerned about recapping, do one at a time.
Do the electrolytics (power supply filter caps) first.
Take a picture before you remove the old cap.
Power it up to verify you did not make a wiring mistake, then do another.

With what you'll learn, I bet you be doing TV sets before you know it.

Thanks for the info. I have posted pictures of this radio with the chassis out in the Vintage TV and Radio Tech Forum. I counted 9 paper caps in the underside of the radio

I've been to the Extravaganza meet a few times, and it is quite an impressive event.

I have a Philco 40-150 (IIRC) that still works on the original caps. With how cramped it is and how rarely I use it I decided to leave it original.

The smaller table sets Zenith and Philco made in that period had VERY cramped difficult to work on chassis IMO....The rubber wire is another thing that ticks me off.

A tip on the recap is to leave long enough lead lengths on the new caps that you can move them around a good ways in case there is something beneath them that you need to make room to work on.

I recommend a set with a more open under chassis layout for a first recap as it is easier to trace the wiring against the schematic if you make a mistake.

I looked at your picture and the speaker is in some real nasty shape.
I remember reading, that it would be about $25 to $40 to recone the speaker. It's a standard 4" speaker, found in most older radios and phonos.
The only thing is, that your speaker has a field coil, used as a choke. The electrolytic caps, have to be increased in value and a resistor subbed in place of the coil.

You could try the 4.5" cone listed from the vendor below and recone it yourself. You might have to trim the new cone down to make it work. You could repair the old cone by carefully removing all of the old "fixes" and making neat ones yourself using a proper paper of the right consistency. Coffee filter paper is OK (but not toilet paper, too flimsy!) and then adhering using fabric glue (buy at a fabric store).

Oops: forgot the URL:

http://www.electronix.com/advanced_s...r+cone&x=0&y=0

Other than the electrolytics, there is one paper cap that is always the most important cap to replace. That's the coupling cap feeding the control grid (G1) of the audio output tube. Any leakage in this cap causes the tube to conduct excessively, shortening the tube's life dramatically. This should be the very first paper cap replaced.

According to Riders, that cap is a .01 mf., part# 38.
Riders shows the tube as 35A5
G1 would be pin 6.

http://www.nostalgiaair.org/PagesByM...9/M0013399.pdf

(Some discussions of this radio suggest the tube is 50L6 or 35L6. In that case G1 would be pin 5.)

I went to the library and printed out the schematic for the radio. Too bad I can't read it. I will be going to a local speaker reconing shop in the next week to see about getting the speaker reconed. I'd rather it be done by a proffesional. I also ordered 13 non electrolytic caps today, so they should get here soon. But what to do about the big blue electrolytic cap. It says "Blu Seal-Dry Electrolytic Cap-80 Mfd red, 50 Mfd blue, Neg. Com. Black" Can you still buy these? What should I replace it with?

Two modern two terminal lytics with the negatives of each connected together to the black lead. 50uF is not a common value so go with a 47uf. As a general rule that era of cap had 20-50% tolerance on capacitance so anything within 20% tolerance of the original value should work fine. If there is no power transformer in your set (as I suspect is the case) the originals are probably rated for 150V so use 160V lytics. On capacitors the voltage rating is supposed to be the maximum safe voltage they will take across them before they go BOOM...So it is always fine to use a higher voltage part than the original as a replacement, but it is BAD to use a lower voltage part.

The scanned Riders schematics and extremely hard to read. The originals in the Riders manuals, seem to be clearer and easier to read.
You don't need an electrolytic capacitor, with that high of a value. If you're using the original speaker, 22 mfd @ 160 wvdc is sufficient. The originals were only 20-20 mfd @ 150 volts.

Electronic M, is this drawing correct for imitating the Blu-Seal? For the sake of simplicity, I put down 50 and 80 mF.

Yup, that is exactly what I was describing.:thmbsp:

Ultimately the exact filter capacitance is not all that critical in these sets. If the originals were both 20uF caps then likely the only differences in operation between the originals and what you have in it now (assuming the current lytics in it are good...which likely is not the case) is lower hum on the B+ line (higher filter capacitance usually=lower hum), and possibly slightly higher B+ voltage.