One thing that people tend to overlook with capacitors is that they eventually dry out... then the magic smoke comes out unexpectedly
They also have a run-time and shelf-life, so given that the caps we are looking at were effectively fresh between the mid 80's to early 90's, we are looking at a rough deployment time of 25 to 30 years. This is definitely outside of a capacitor's nominal operating lifespan.
So, if we take those dodgy caps which are certainly not operating optimally, and replace them with modern less noisy versions, then the overall stability of the machine concerned can be increased. Noise is a massive problem in Atari machines, and always was, so anything that improves the matter is highly welcome.
The solution Chris has here is really nice and is much simpler to maintain over a longer period of time. So, willy, I'll point out that it is currently broke, and definitely needs fixing; if not for fixing the screen dimming during floppy access problem alone. With further development, there will be other large capacitors that can be replaced with low-profile versions, and there is the added bonus of possibly using cermics at a future date.
So, Willy, if that still sounds like Voodoo to you, then I highly recommend reading some electronics introduction books. There is also a really good deal for the next two days on some Make books via a Humble bundle as well: https://www.humblebundle.com/books/make-arduino-and-raspberry-pi
I found those particular deals to be quite interesting, and the make bundles have periodically had various electronics encyclopedias which are a very informative read.