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Post by DHockey on Apr 21, 2020 16:36:50 GMT 12
Has anybody else noticed the transatlantic divide when it comes to the controversial topic of reforming capacitors? It appears reforming is much more popular in the UK than in the USA judging from forum posts on the topic. On the UK forums whenever someone gets a new Bush DAC90A (seemingly the only valve radio that exists in the UK  ) The consensus is that the main filter caps will be fine after reforming, even if the set is in poor condition and not powered up for years. In the USA on the other hand, there is more of the “if it makes a noise when it lands in the trash can, its bad” school of thought. People asking about reforming are in no uncertain terms warned that they are gambling with their power transformer’s life! Personally, I have no restored radios in my collection with original filter caps, I replace and or re-stuff them as a matter of course. I have played around with reforming old caps as a bit of an experiment, but even in new-old-stock cans the leakage has returned to high levels after just a couple of days. Whereas new Panasonic or Rubycon caps will go to well under 1 milliamp of leakage very quickly after application of voltage, even after months of storage. I’m interested to find out what the NZ take is on reforming, anyone here do it? |
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Steve
Society Members
vintageradio.co.nz
Posts: 727
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Post by Steve on Apr 21, 2020 18:21:11 GMT 12
In a previous life involving a lot of saluting I had a job for a while that involved removing individually wrapped NSN-coded capacitors from their foil sealed bag, re-forming them then re-sealing them again. T'was a long time ago, and the details are shady, but I think these were NOS at around 10 years old. I consider any cap from the UK to be shady, but thats probably mostly my internal bias against Hunts... which was slightly mitigated by this post I read a while back containing info from a former Hunts employee, but not completely To answer the question though - I think certain forums get 'personalities' from the more prolific members, and if one of those suggests reforming then others who aren't so sure will tend to pick that up and go with it for no good scientific reason. I've heard people saying re-forming is ok on US forums, but they get shot down pretty quick. I re-form nothing - capacitors are guilty and have no chance to prove themselves innocent in the court of my workbench. Even the ones that seem fine are just waiting for me to turn my back so they can spew their internal organs all over the place. I get the concept, but you're dealing with damaged material and I don't think you can re-form the paper layer by bringing voltage up slowly...
Capacitors are cheap, volts are high, replace 'em. Someone will disagree though, and I'm always happy to be wrong 
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Post by Richard on Apr 22, 2020 21:25:03 GMT 12
Agree, just replace them, I want my radios to be reliable
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) The consensus is that the main filter caps will be fine after reforming, even if the set is in poor condition and not powered up for years. 
