[Coco] Re: Old radios

KnudsenMJ at aol.com KnudsenMJ at aol.com
Thu Mar 11 22:56:34 EST 2004


In a message dated 3/11/04 9:41:54 PM Eastern Standard Time, 
jdaggett at gate.net writes:

> That is one way of reforming caps. Another is to remove them and 
>  slowly work the voltage up across the cap while limiting the current. 
>  Once you get them up to full working voltage then you can leave 
>  them at that voltage for a while.The one thing that is death to those 
>  capsis to hit it with to much current when the dielectric is not well 
>  formed between the plates. 

True.  Do keep in mind that there are some old electrolytic caps that are 
beyond salvation with this method.  No matter how long you let them re-form with 
a trickle of current thru the resistor, they never quite stop leaking too much 
-- so much that if you put them back into their circuit and run full power, 
they will overheat, or even draw so much current as to burn out your 
transformer or melt the plates in the rectifier tube (if they glow red hot, power down!).

Worse yet, old caps like this may seem to reform just fine, and play along 
for days, and then one day -- BAM!  they let all the smoke out (and tar, and 
chemicals the Govt. didn't know about in 1930-whatever).  Don't ask how I know.

If you really want to playt he radio and show it off (and you should!), there 
are place to buy authentic replacement parts.  Those newsgroups I mentioned 
are a good place to start looking.

Enjoy your radio -- but safely -- Mike K.



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