I really did not know this was a thing. But it seems TI have chips which can improve common mode performance of EMI filters, by actively driving the "Y" capacitor so that smaller CM chokes can be used.
(No, I'm not a shill for TI.)
https://www.ti.com/power-management/power-supply-filter/overview.html

A friend of mine has given me the CO2 laser out of his laser cutter - the output has become weak, suggesting regassing is needed.  Sadly the cost of shipping to the US to get it refurbished is more than the cost of a whole new Chinese laser, which is why I've been given the old one.

The laser is a sealed 75W RF driven one made by SYNRAD in 1998. 
Its a beautiful thing, with a couple of RF drivers and a control board mounted in an extruded aluminium housing.   Reading the patents (patent numbers are on the outside of the case) it looks like internally the laser cavity also consists of aluminium extrusions, with transverse excitation from RF drivers operating at about 50MHz.

Has anyone here attempted to re-gas a laser?  I realise the original gas mix will be some proprietary secret, but generally its about 8-10% CO2 with the balance being nitrogen and helium. Sometimes a little Xenon is added, or some CO, both are meant to extend the life of the sealed tube. There's also usually a gas regenerating catalyst internally.

I know I'll never get it as good as the original, just trying to decide if its worth trying to regas it myself. Getting a few hundred hours per refill would be worth it.  Just need the gas handling valves, and a vacuum gauge, as I already have a pretty good Edwards vac pump.

A colleague is trying to replace film caps with electrolytics in a heavy pulse application (electric fence shock driver).
Does anyone know what failure modes are likely for an electrolytic driven well beyond its ripple current rating? These caps are not pulse rated AFAIK.

Pulsing is 1 to 3 pulses of ~50usec ~50A pk, from 5uF, every few minutes.  I'm concerned the very high discharge current may cause internal damage that is not immediately obvious.