Thanks, Lugia! Can I ask you some stupid questions?

Thanks for the PS recommendation. Just ordered it :-)

What would I replace the red wire with? I would assume that the the red and black are either 12v or -12v--and I do have a problem knowing which is which.

Also, dumber question, I presume you're talking about the red wires going to the distro boards? And not the inputs from the power switch that attach to the PS?

I pulled up one of the boards and....amazingly...no writing whatsoever!

https://imgur.com/a/GDQFMT6