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#11
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Howard Bingham wrote: One question, what are "paper capacitors" & how do they differ from those found on other radios..? (One of the contacts who aparently services these old German radios suggested replacing the paper capacitors before replacing tubes.). Howard Bingham, Houston, Tx. KE5APJ Most radios have three basic kinds of caps - electrolytics, which have large capacitance values and show up in the power supply and the audio output, tubulars, which have middling values and show up all over the place, and small-capacitance ceramics. Ceramics are usually small plastic disks or lozenge shaped, and rarely fail. The electrolytics in older radios are almost always bad and need replacing. Older radios had tubular caps which used wax-impregnated paper to separate the foil "plates." The wax-paper degrades with time and they usually need to be replaced, though I have seen plenty that are older than your radio that are still OK. You should definitely replace the electrolytics and any paper caps that are in the power supply before replacing any tubes or else you may well have to replace the tubes again right quick (as the saying goes, "Ask me how I know"). |
#12
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Forgot to mention, the tubulars can be replaced with modern mylar, polyester or polypropylene tubulars or (overkill) orange-drops. AES or radiodaze or any number of on-line vendors have them. The yellow poly tubulars are cheap and reliable and easy to work with. The capacitance values will not likely be exactly the same as the originals, but within 10% or so is fine. Err on the high side for electolytics. Another fine source for caps is Dave & Babylyn Cantelon at www.justradios.com. They also have schematics for some US, Canadian and European radios, you might ask them if they have one for your radio. |
#13
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Howard Bingham wrote:
Thank you for all of the replies, I have contacted several links which have resulted in some positive feedback as to this restoration project which started as a rainy day idea to fix up this Blaupunkt radio that had until this weekend been collecting dust on top of a book case.. One question, what are "paper capacitors" & how do they differ from those found on other radios..? (One of the contacts who aparently services these old German radios suggested replacing the paper capacitors before replacing tubes.). Howard Bingham, Houston, Tx. KE5APJ You'll need to go to this newsgroup: rec.antiques.radio+phono I'm sure you can find people who work on old German sets there, and if this little holiday project is shaping up to be more than you can handle, maybe you can get one of them to fix it for you. ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
#14
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Volker Tonn wrote:
Howard Bingham schrieb: One question, what are "paper capacitors" & how do they differ from those found on other radios..? (One of the contacts who aparently services these old German radios suggested replacing the paper capacitors before replacing tubes.). Paper capacitors are made with paper inside as the name implies. These capacitors tend to dry out and tend to explode sooner or later, destroying a lot inside the radio. So a replacement with modern parts/ capacitors is highly recommended. It's been my experience that paper capacitors rarely explode. They just become leaky to DC current and therefore ineffective for their intended purpose as an AC signal device. Replacing them can protect other components such as I.F. transformers which can be hard to find for old tube radios. ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
#15
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They do explode. They'll fill a large room with little bits of
aluminum foil and wax paper. On Tue, 30 Nov 2004 03:19:03 -0500, starman wrote: Volker Tonn wrote: Howard Bingham schrieb: One question, what are "paper capacitors" & how do they differ from those found on other radios..? (One of the contacts who aparently services these old German radios suggested replacing the paper capacitors before replacing tubes.). Paper capacitors are made with paper inside as the name implies. These capacitors tend to dry out and tend to explode sooner or later, destroying a lot inside the radio. So a replacement with modern parts/ capacitors is highly recommended. It's been my experience that paper capacitors rarely explode. They just become leaky to DC current and therefore ineffective for their intended purpose as an AC signal device. Replacing them can protect other components such as I.F. transformers which can be hard to find for old tube radios. ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
#16
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"Howard Bingham" wrote in message ... Thank you for all of the replies, I have contacted several links which have resulted in some positive feedback as to this restoration project which started as a rainy day idea to fix up this Blaupunkt radio that had until this weekend been collecting dust on top of a book case.. One question, what are "paper capacitors" & how do they differ from those found on other radios..? (One of the contacts who aparently services these old German radios suggested replacing the paper capacitors before replacing tubes.). Howard Bingham, Houston, Tx. KE5APJ Take a look at the "How can I fix up my old radio?" and "How to replace capacitors" articles on Phil Nelson's helpful Radio Beginner page: http://antiqueradio.org/begin.htm Frank Dresser |
#17
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In article Q0Pqd.799$8v3.447@trndny08,
Larry Ozarow wrote: Howard Bingham wrote: One question, what are "paper capacitors" & how do they differ from those found on other radios..? (One of the contacts who aparently services these old German radios suggested replacing the paper capacitors before replacing tubes.). Howard Bingham, Houston, Tx. KE5APJ Most radios have three basic kinds of caps - electrolytics, which have large capacitance values and show up in the power supply and the audio output, tubulars, which have middling values and show up all over the place, and small-capacitance ceramics. Ceramics are usually small plastic disks or lozenge shaped, and rarely fail. Older radios will have mica capacitors in place of ceramics, which became popular in, judging from the stuff I've scrapped over the years, in the 1950s. They look like little black or dark brown dominos. Mark Zenier Washington State resident |
#18
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On Tue, 30 Nov 2004 03:19:03 -0500, starman wrote: Volker Tonn wrote: Howard Bingham schrieb: One question, what are "paper capacitors" & how do they differ from those found on other radios..? (One of the contacts who aparently services these old German radios suggested replacing the paper capacitors before replacing tubes.). Paper capacitors are made with paper inside as the name implies. These capacitors tend to dry out and tend to explode sooner or later, destroying a lot inside the radio. So a replacement with modern parts/ capacitors is highly recommended. It's been my experience that paper capacitors rarely explode. They just become leaky to DC current and therefore ineffective for their intended purpose as an AC signal device. Replacing them can protect other components such as I.F. transformers which can be hard to find for old tube radios. David wrote: They do explode. They'll fill a large room with little bits of aluminum foil and wax paper. I used the word 'rarely' for a reason. I have never had an original waxed paper capacitor explode in any of my boatanchors during the past 30-years. That doesn't mean it never happens. I usually replace them because most are leaky, especially the infamous 'black beauties'. ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
#19
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In article ,
Howard Bingham wrote: There remains only one tube to be found & I have 4 vendors looking for the US equivilent if not the exact replacement tube. ( ECC85 ) 6AQ8, E(xcellent) replacment according to my Rider Receiving Tube Substituion Guide. (If you had put a list of the numbers in your first post, you'd know this by now). Mark Zenier Washington State resident |
#20
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Mark Zenier wrote:
In article Q0Pqd.799$8v3.447@trndny08, Larry Ozarow wrote: Howard Bingham wrote: One question, what are "paper capacitors" & how do they differ from those found on other radios..? (One of the contacts who aparently services these old German radios suggested replacing the paper capacitors before replacing tubes.). Howard Bingham, Houston, Tx. KE5APJ Most radios have three basic kinds of caps - electrolytics, which have large capacitance values and show up in the power supply and the audio output, tubulars, which have middling values and show up all over the place, and small-capacitance ceramics. Ceramics are usually small plastic disks or lozenge shaped, and rarely fail. Older radios will have mica capacitors in place of ceramics, which became popular in, judging from the stuff I've scrapped over the years, in the 1950s. They look like little black or dark brown dominos. Those micas are surprisely reliable for their age. I seldom have to replace one but it's a good idea to check them. ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |