Hi,
Frank wrote:

I think we can both say with confidence that Ducati got the electrolyte
formulation right, way back two or three decades ago. I didn't measure
any significant change in capacitance or ESR (except ESR went up on a
couple on the last test). If they had a +/- 20% tolerance, they were in
spec at the start and stayed in spec at every step of the test. But I
never noticed a big change when I've checked electrolytics before.

I didn't find any big changes either, measuring high-voltage
electrolytics from as far back as 1947. Looking at your data, within
the limits of experimental error I don't see any changes at all. That
pretty much kills the myth about capacitors reforming to a new working
voltage and changing the oxide-layer thickness.

However I'm sure we haven't seen the last of it. I believe there's
still a website with quotes from Deeley's book on electrolytic
capacitors. What it doesn't say is that this book was published in
1939.

73, Alan