On Thursday, December 5, 2019 at 5:11:08 AM UTC-5,

My uncle, a frail 86yo EE, insisted he could fix it by just finding the bad
twenty five cent capacitor. And I've seen him fix bad capacitors by just
tapping them. (He sepnt the 1950s on WW2 submarines the USA give Greece.)


Old timers used to (allegedly) *fix* bad electrolytics by tapping them with the back end of a wrench. These were the metal chassis mount varieties, and banging them would compress what was left of the electrolyte inside. Squeezing with pliers was another option. Be aware that I heard of this as a lad back in the 1960s, so this would have been on older types caps, not what we see today.

Compressing those old style metal can caps might have bought some time but I think squeezing modern paper electros would do no good at all. When I get to work, I'm going to try that on some bad caps and see if there's any improvement in value and ESR.

Getting back to your problem, I think gramps is right; it's probably a tired electro (that would be "swell"). These almost invariably work far better when heated, so if the brick was sitting in a warm area, it might spring to life. Alternatively, you can heat the brick with a hair dryer or heat gun to get it to work, but these are only temporary solutions. Crack the bricks open and change the electros with the bulged tops. That will get most running. If not, you'll have to either ESR or replace the rest of the caps. Lower value caps on the primary side of the SMPS bricks generally go weak but don't swell or bulge.