Portadyne and Noble 'twins'

[Yorkie]

David, Nice job as usual, with an informative write up.

Could you post details of the cap reformer in homebrew?

cheers Mark

I did do Mark, back in May last year, but I've just updated the posting and have added the pics that disappeared along with others on the forum when it hit the skidpan last August or whenever.

One of the items that proved elusive to find was a MOSFET, and I was able to get one cheaply from Chris Tredwell at Mode Components but Chris retired in April, so anyone contemplating building the project, which featured first in Radio Bygones and later in the BVWS Bulletin in 2008, would need to ensure they can get the MOSFET from somewhere. The other sources of the digital panel meter, the analogue meter, the transformers etc are still current.

Here's the link:

http://golbornevintageradio.org/forum/sh...hp?tid=620

Not difficult to build, and it works well. You build up the voltage and the current in steps over time as the leakage reduces (hopefully!) during the reforming process.

The article gives a formula for calculating the time needed to reform a capacitor, namely: T (in minutes) = 5 + M,where M is the total number of months that a capacitor has been in storage unused. So for example, if a radio (or NOS electrolytic cap) has been in storage for 40 years, the total time needed to reform it is 5 + 40 x 12 = 485 minutes - about eight hours. (That formula is a general one for any reforming method - not just with this particular reformer).

Hope that helps.