Hello @JColvin@jpeyron,
I'm facing with exactly the same issue: I suddenly could not power on my Zedboard, which worked pretty fine last month. Just after bringing it to Washington this board failed to start, which was really weird.
The LD13 power light doesn't flash, or to say I can't detect any valid power stages for the capacitors mentioned above. The adapter works since I can detect 12V using DMM on J20 port, but there's no voltage on the switch (SW8) when turned on. Btw I just recognize there's a 8V voltage on element F5, which seems abnormal.
I'm using Rev D version, and this board was purchased an year ago, around Mar. 2020. Please kindly provide any suggestions! Thanks in advance!