8 Volt system w Radio
April 20th, 2010, 06:26 AM
#1
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Join Date: Dec 2008
Location: Southwest
Posts: 18
8 Volt system w Radio
Ok I like the way my old 49 starts with an 8 volt battery. But now I am told that is what cratered my radio! I bought all new tubes, but I was told that the capacitors are probably blown and replacing them won't work unless I get some rated for higher voltage.. Where do I look to get such things? What if I can't read the values on the old ones? Are there schematics that give the component values for the radio? I really hate hanging a transistor radio on the rearview or paying $400 plus to fix the original. I have more time than money...
April 20th, 2010, 06:42 AM
#2
Past Administrator
Join Date: May 2004
Location: Rural Waxahachie Texas
Posts: 10,025
Send your radio to this guy and tell him your predicament. He might be able to help you. You might also look for a step-down transformer if he can't convert your radio to 8 volt operation. Either way, I bet he can help you out.
April 20th, 2010, 08:55 AM
#3
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Join Date: Feb 2008
Location: Plano, TX
Posts: 11,798
The electrolytic and paper caps may be either shorted, shorting, or have just lost their capacitance over time. Replacement is easy, as the physical sizes have decreased substantially over the past 50 years!
The metal canned caps are the ones to usually go and they are usually marked with mfd and wv (working voltage). High voltage caps are still plentiful for tube use. Photoflash caps can work well.
Caps can be had at many electronics parts suppliers like MCM, mouser, digikey, all electronics, BG Micro, and other places.
Voltage is critical to avoid eruption. The capacitance rating can be slightly higher if an exact match is not available. Remember typical tolerance was +/- 20% anyway...
I have recapped old radios and phonos with good results.
Antique radio websites will tell a lot about recapping tube sets.
Here is one to get you started:
http://www.antiqueradio.org/recap.htm
However, if your experience is limited in tube equipment, it might be best left to a pro. High voltage is always a hazard.
Bobs radio (link above) have gotten good press so far - see what they say!
There is nothing nicer than listening to the original tube radio in that age of car!!
(Get an AM transmitter and you can even enjoy mp3s played through the original radio!)
The metal canned caps are the ones to usually go and they are usually marked with mfd and wv (working voltage). High voltage caps are still plentiful for tube use. Photoflash caps can work well.
Caps can be had at many electronics parts suppliers like MCM, mouser, digikey, all electronics, BG Micro, and other places.
Voltage is critical to avoid eruption. The capacitance rating can be slightly higher if an exact match is not available. Remember typical tolerance was +/- 20% anyway...
I have recapped old radios and phonos with good results.
Antique radio websites will tell a lot about recapping tube sets.
Here is one to get you started:
http://www.antiqueradio.org/recap.htm
However, if your experience is limited in tube equipment, it might be best left to a pro. High voltage is always a hazard.
Bobs radio (link above) have gotten good press so far - see what they say!
There is nothing nicer than listening to the original tube radio in that age of car!!
(Get an AM transmitter and you can even enjoy mp3s played through the original radio!)
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