[ARC5] Reforming capacitors????

[J. Forster]

This topic comes up time and again. What puzzles me is those who dismiss my
method as wrong, without trying it. What do you really have to loose? If it
doesn't work, you've lost nothing except a few minutes of setup time and a few
days to wait while it works. If it does, you have a working, all original radio,
which is much more valuable than a radio that has been chopped up during
re-capping.

As to placing the unit in an oven, that tends to cause other problems such as
migration or drying of lubricants.

Your opinion may vary.

Mike Feher wrote:

> Ken -
>
> I am of the same opinion as you are. I believe what John is doing is heating
> the capacitor by utilizing its leakage resistance to the point where some of
> the moisture causing the leakage evaporates or essentially slowly boils out.
> Then, raising the voltage, he gets the remaining moisture causing the
> leakage. If this method indeed works, then I would think placing the
> capacitor in an oven set at a low temperature would accomplish the same
> thing. Unfortunately I also believe that at the same time that the moisture
> slowly seeped in over the years so did other contaminants.

Such as what? Water is a pretty small molecule. I am unaware that significant
concentrations of ionic compounds can be transported that way.

> I believe the
> majority of the leakage is probably due to the other contaminants which will
> be almost impossible to remove, hence the leakage is there to stay. One
> thing for sure, if the applied voltage ever causes the dielectric to
> carbonize it is all over. 73 - Mike

That's why you apply the voltage from a current limited supply, and gradually.

-John

>