Hello All, I thought I might introduce myself before asking 67 questions. My name is Jay and I live in a small town outside of Kansas City. I have been fascinated with vacuum tubes for a few years, mostly in Hi-Fi systems. I know just enough to get in trouble most of the time. I have for the most part done minor repairs and lots of re-caps and cleanings, allthough I have built one single ended triode amp from scratch. As far as antique radios go I've had a couple of Zeniths for several years, but never a Philco until today. I acquired a very pristine model 511 complete with the seperate speaker. It was looking for information on it, that lead me here, where I browsed for the better part of the day. I read one post where a fellow said he had a 511 running on the original electronics. I figured what the heck, and prepared to test out my new treasure. I started by testing all the tubes, and found two of the four 26s to be bad. Interestingly enough the two that were good were branded Philco, and the bad ones were a Tung-Sol and an RCA. Anyhow, the #80 rectifier was fine, as was the 27. I do not have the settings for any of my testers to check the 117 (final output?). I replaced the two bad 26s and plugged her into my variac. I very slowly over about an hour, brought the voltage up while monitoring the watts. It is rated for 50, and settled in at 54 at 105 volts. There was no release of magic smoke or sound. I looked underneath and checked the 2meg resistor which was fine. I removed the cover that houses the primary transformer, huge capacitor?, and what appera to be two chokes stacked one on top of the other. The bottom choke had 150vdc in, and 139vdc out. The top choke had ~12vdc in and nothing out. I'll be honest and say that this big radio is pretty much greek to me, and the last thing I want to do is damage an unobtainable part that has survived since 1928. This old girl is a true survivor and deserves the best. I am open to any and all suggestions, and appreciate same, Jay
BTW- I have pics if someone can tell me how to post them.
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Hi Jay
Welcome to the Phorums! I was born in Kansas City but have not lived there since I was 12. I remember the old McGee Radio Co., downtown, and Burstein-Applebee, too; two large electronics wholesalers. I know B-A is long gone, I think McGee Radio is also?
Anyway, on to your 511. Your audio output tube should be a Type 71A - may be labelled 171A, but test it as a 71A once you confirm that is the proper number on the tube you have.
One of the two filter chokes is in the positive leg of the power supply (the one which you measured 150 in, 139 out). The other choke is in the NEGATIVE leg of the power supply, and one end connectes to chassis ground - which has to be where you measured 0 volts, which is normal if you are referencing your measurements to ground.
Go and check the multi-section voltage divider resistor, labeled (37) and ( 38 ) on the schematic. Bear in mind that on most 511 sets, the 70,000 ohm section of (37) is a separate resistor, mounted away from the main divider. I'd be willing to bet that one or more sections of this resistor is/are bad, which is commonplace. Those bad sections will need to be replaced with new resistors before your set will come to life.
If I were you, I would replace ALL capacitors inside the large metal can (35), as well as the paper caps inside the cylindrical tubes (7), (12), (17), (39) and rectangular metal cans (27) and (30). Capacitors (7), (12) & (17) also have 100 ohm resistance windings around each cylindrical tube; this resistance wire often breaks and kills your set. Replace with 100 ohm resistors hidden inside the old cylindrical tubes as you replace the capacitors in each.
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Ron Ramirez
Ferdinand IN
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Ron Ramirez
Ferdinand IN
Thanks for the reply Ron. I just got a schematic today, and will study it tonight paying special attention to the items you mentioned. That's a pretty neat choke arrangement, which is new to me. Generally on Hi-Fi there is only one in the DC filter. I'll keep you posted on my progress, and work on getting a picture up. Thanks Again, Jay
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Hi Jay,
I'm in Lawrence and have just gotten into restoring radios this past summer. I'm always looking for other folks to teach me some stuff.
Ryan
