Been stuck for awhile on making progress because during one of the HPL runs the system suddenly lost power.  Turns out that the barrel connector for the power supply failed, most likely due to overheating.

I have plans to completely replace the power supply (including a battery) and figured I'd just leave this alone until I had that system ready, but it's been over a month now and I'd like to get back to work.

So for now I've decided to work-around the problem by using the ATX connector on the clusterboard to power it, and I've switched to a beefier supply as well so that I can kick these power problems down the road a bit.

This won't be the long-term solution to the problem, but it gets the lights back on for now.

(next step is to print something to cover those exposed mains terminals though...)