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Antique Radios

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pdplot

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I replaced two tubes in the old GE but no improvement - still only gets 2 AM stations and not very well. Fuzzy. BUT - this is important! I looked online and learned about the dangers of working on old radios. Some of them have live chassis and if you are grounded, as much as 400 volts can pass though your body, stopping your heart and killing you dead. Even with the non-directional plug out, you can still get a bad shock from undischarged capacitors. My radio has a transformer to reduce the voltage so not much chance of electrocution but I didn't read this stuff until I had pulled the chassis out of the cabinet and fiddled around with things. If you want to scare yourself, go online and Google working on antique radios.
 
Wow - a good warning to others to check details/schematics *before* opening up the case.

Paul, what type (solid vs stranded) and length of antenna and ground wires are you using? I've found major differences in reception depending on those details, as well as direction the linear antenna is oriented. Also too sensitive to 60 cycle hum I'm afraid.

Tom M.
1930 Atwater Kent 70
IMGP6020.jpg
 
Only a 3' length of solid wire and no ground. Plus it's in the basement but so is my Telefunken Rondo and that gets good reception. Lots of hum also.
 
Thanks. I'm out in the sticks, so the AK recommended 30' solid wire antenna, straight line, works for me. But very directional.

Your Rondo is a 1950s radio; what year is your GE?
 
I believe it's a 1936 vintage. I think I have a picture. Here it is. The cabinet is actually darker.
 

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  • GE Radio.JPG
    GE Radio.JPG
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Thanks Paul. Old sets like that usually need a *long* antenna, plus a separate ground wire.

Any idea what GE model that is? Looks like a Model 51. You can find schematics at:

L-51 Radio General Electric Co. GE; Bridgeport CT, Syracuse, build |Radiomuseum.org

L-51 Radio General Electric Co. GE; Bridgeport CT, Syracuse, build 1934 ?, 3 pictures, 5 schematics, 5 tubes, United States of America , semiconductors
www.radiomuseum.org www.radiomuseum.org

Tom M.
 
pdplot said:
I replaced two tubes in the old GE but no improvement - still only gets 2 AM stations and not very well. Fuzzy. BUT - this is important! I looked online and learned about the dangers of working on old radios. Some of them have live chassis and if you are grounded, as much as 400 volts can pass though your body, stopping your heart and killing you dead. Even with the non-directional plug out, you can still get a bad shock from undischarged capacitors. My radio has a transformer to reduce the voltage so not much chance of electrocution but I didn't read this stuff until I had pulled the chassis out of the cabinet and fiddled around with things. If you want to scare yourself, go online and Google working on antique radios.
Click to expand...
If you are interested in troubleshooting and antique electronics check out Mr. Carlsons Lab on youtube... the best and an incredible teacher. He has an electronics lab in his house which rivals NASA...
 
Any tube type device can knock you on your butt. I always tell people, If you do not have at least "basic" understanding of electricity, AD,DC Ohms,Watts ect... Do not play with tube type stuff. It will hurt you. Field coil speakers especially!! I spent 19 years teaching this stuff years ago and even I get wacked once in a while when I'm not careful. George
 
George_H said:
Any tube type device can knock you on your butt.
Click to expand...
When I worked on the NORAD SAGE computer system (all vacuum tubes), we always had to have a safety observer with us any time we were going to do anything that required getting near components that could be dangerous. I remember one time I was doing some preventative maintenance on one of the power distribution units (on left in picture). TSgt Ed Brace was my safety observer. As I was attaching a meter to a measuring port to check the voltage levels on a 600v supply, I suddendly had a jolt like I've never felt before or after. Even though I had safty gloves on, the jolt was enough to send me back on my heels several feet. My first though was that for some reason Ed had hit me upside the head with a two by four.

35013352652_d7934aa205_b.jpg
 
Basil - any idea why you got shocked? Seems like a nasty surprise!

Paul - try a much longer antenna on that GE radio. Should greatly improve reception.
 
NutmegCT said:
Basil - any idea why you got shocked? Seems like a nasty surprise!
Click to expand...
Nope. Possibly faulty safety gloves. Had rubber sole shoes and was standing on safety mat. Might have brushed arm above the gloves against something, but that just a guess.
 
Back in the day, I used to do TV repair. A crack in the high voltage lead going to the CRT would sometimes give you a nasty suprise.
25KV would ark to you if you got within an inch or 2. Thank God it did not have much current behind it.
 
George_H said:
Back in the day, I used to do TV repair. A crack in the high voltage lead going to the CRT would sometimes give you a nasty suprise.
25KV would ark to you if you got within an inch or 2. Thank God it did not have much current behind it.
Click to expand...

My dad demonstrated the dangers of HV when I was quite young. He grounded the CRT supply to the chassis on a set, it made a lasting impression!
 
Eh, transformer powered sets usually step UP the voltage for the plate supply as well as dropping the voltage for the tube heaters. Tubes typically work at 100 volts or more for the plate supplies. Transformerless sets are hazardous because the chassis can be tied to the hot side of the plug even if they are not turned on.

Got a nasty shock off a 1937 Truetone I was troubleshooting. Somebody before me had turned the band switch past the stop, so the antenna lead was going to the 350 VDC plate supply of the oscillator tube instead of the antenna coil. Had the chassis out, schematic ready, was checking voltages, and when I reached over to grab something, I bumped against the antenna wire - while I had my other hand on the volume control shaft. :oops:. Welp, I found the problem, after my arm stopped tingling.
 
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