I'm gonna try once more with the antique radios
 

FOREWORD...

Last March, I made a terrific mistake which cost me my beloved Philco 41-231. I have since joined the Alabama Historical Radio Society. They have a very well equipped workshop with all the parts you could ever need. They are also a treasure trove of valuable radio knowledge. I have not been to the weekly Saturday meeting since May, so when I go back there this weekend, intreresting things might happen. IF IT AIN'T BROKE DON'T FIX IT!

I picked up this lovely 1942 Philco 42-372 at the flea mall today for only $18.00. That's pretty good compared to the prices on ebay. I will be taking it to the AHRS this weekend in hopes of getting it working again.

That'll be a pretty schnazzy Philco when you get it done, don't get discouraged if you don't get it working right away its just a hobby it doesn't matter if it takes all year.

The model number is really 42-327, listed on Philco Radio.com.
Another fun Philco, to restore. Patience is really a virtue here. More rubber wire here. I hope the speaker is good on this one.

Oops. I mixed the numbers up.

I got this radio working today. My favorite AM music station has sadly dried up, so I have nothing to listen to until midnight. I've been told that there are small AM transmitters that can be plugged into an MP3 player or smartfone. Does anyone know anything about that?

I've been listening to Coast to Coast for the past hour, and I've noticed a strange phenomenon with this radio. For the first five or six minutes of operation, George Knapp comes in crystal clear. After six minutes have past, the audio slowly starts to degrade. Until after eight or nine minutes, the volume is turned halfway up, and the sound is extremely scratchy. I'm fairly certain that this is a tube. If I turn it off and let it cool down, then turn it back on, it sounds good again and the cycle repeats.

The audio coupling capacitor is leaky, driving the output tube grid positive.
The output tube is probably bad too.
That cap has to be replaced, first. :sigh:

Is there an easy way to indentify this capacitor? I plan to go back to the AHRS this Saturday and clean all the tube holders, check all the tubes on the military tube tester, and replace a few capacitors. Not to mention fix the dial cord.

The audio output tube is a 50L6... one end of the cap will be connected to pin 5 of this tube, the other end to pin 2 of the 7C6 detector/audio amp.

jr

Thank you.

Looks like I found the problem.

That's the cap, #40 on the schematic.
Replace it before you go to the meet! Then try it. Even if the tube is questionable, there should be an improvement. You still might have to replace the tube, for best results.

I have neither the materials nor the space to properly replace a capacitor at this time. I always wait until Saturday before I start any work on my radios.

I replaced the 50L6 tube with a known working genuine Philco tube, and that solved the problem. The doofus who owned this radio didn't insist on genuine Philco tubes. The tube at fault is an RCA Radiotron Electron tube.

First I want to say that it must be absolutely wonderful to have a place that you can go with all this equipment, parts and knowledgeable people. Weekly meetings and all. My mom is from Shelby, Alabama. Makes me wish I was there because in most places it seems like most people are just worried about the latest 'smart' phone!:no: I always feel like the only backwards a** person in existence anywhere around here that gives a darn or knows about old radios and TVs. TV collecting really can get you the hairy eyeball! LOL!

Finally, that previous owner just bought whatever tube he could find at the local dime store or repair shop. RCA made great tubes; so did Philco. The tube just went bad....

Thank you. It's one of the two merits of living in Birmingham. The other is Milo's Hamburgers.

The Mix of tubes in a radio or TV can sometime give a clue as to how long it was used. For the most part all radios and TV's where populated with manufacture branded tubes, there are rare exceptions to this though. As the set gets used the owner starts putting in different brands when old tubes go bad. That is of course unless that did insist on factory branded tubes or lived in a small town and only had one choice. The more motley mix of tubes the longer it was probably used.

I have an RCA 14" portable set I picked up only the Rectifier and CRT where still RCA and of the tubes installed 14 out of 23 tested very weak or had shorts.

This is the only non original tube.

Did you ever get either of those VCR's working?

Philco used tubes made by Sylvania and RCA. All the loctals were Sylvania and many of the octals were either Sylvania or RCA. The original 50L6, could be easily RCA sourced.
For some reason, Philco used a lot of variations in their tube line-ups. The schematic, from the radio in question, shows either a 35Z5 or a 35Z3 and the difference in the pilot light wiring.
BTW, the coupling capacitor, #40, still should be replaced, otherwise the new 50L6, can be damaged. :nono:

Take a close look at your "Genuine Philco Tubes" for MFG codes, I suspect that you might find codes for RCA (274) or Sylvania (312) stamped on the tube, along with date code letters or numbers. More info here:
http://www.triodeel.com/eiacode.htm

jr

I agree about changing the cap... it may well have caused the failure of the RCA 50L6.

With the help of another AHRS member, we got the dial cord "fixed." That is to say, it is attached, but the tension is a little weak and the pointer is not connected. I checked the tubes on the tube tester and replaced a few. We glued a hole in the speaker and replaced some capacitors. I made sure to replace the cap mentioned earlier in the thread. Next time, I want to get the dial cord finished and get a few more capacitors replaced.

Pre-war tubes didn't have the EIA codes on them. Philco tubes didn't have it until the late 40's, as well as Silvertone and some other tubes that were supplied by Sylvania. :sigh:

After some fiddling, I was able to get the shortwave function to work. I was able to pick up several British stations, one in Spanish, and one I believe in Japanese. That's pretty cool that I can pick up stations halfway 'round the world.

The tube went bad most likely because cap #40 is leaky and needs to be replaced, if not replaced the new tube will go bad as well. Philco did not make tubes, they bought them from other manufacturers and had their name put on them. I do believe I read someplace that Sylvania made Philco tubes, cant recall for sure though.

Gregb

As a restorer and an Electrical Engineering student less than an academic year from graduating; I can tell you that contrary to any claims by marketing departments one brand of tube was almost never better than any other...The exceptions were where circuits pushed tubes too far (such as the RCA CTC-17 tv IIRC ate 6GH7 tubes like candy and some brands could take the abuse better), tubes that were originally bad designs (many 6X5 tubes were prone to shorting and destroying the power transformer, however some brands later improved the design to make it safer), and some off brands (places that did not make radios/TVs/electronics or rebadged the cheapest crap they could get)particularly the budget and Japanese brands would produce inferior product and/or do other fishy stuff.

And definitely change that cap!

Didn't y'all read my post? I already replaced the cap!

Good to see your are getting that radio back in shape!

As for your SL-5000 there are TONS of caps in it, but the problematic ones are the Blue Sanyo caps, replace them and then you might be getting somewhere

I WAS going to go to the meeting today, but I overslept 3 HOURS on account of being forced to go to an INCREDIBLY STUPID HIGH SCHOOL FOOTBALL GAME!! God how I DESPISE the game.

Just remember though Football and baseball spawned some of the best announcers, and some awesome innovation in radio and tv. it also sold and continues to sell LOTS of sets. Although not enough to make the fraud that was 3D TV take off :)

I understand getting away from radios. I got burned by a few customers back in the early 90s and got out of them. After my daughter left for college I got back into them a couple of years ago. If you want to go to another meet in Tennessee the group in Nashville meets this Saturday. You can find folks to ask questions of if you need to there until your regular meet. Here is info to it.

http://musiccityvintageradio.wordpress.com/