Peter Easthope wrote:

OK. With the tab at the bottom of the well shorted to the perimeter
shield it still won't boot. Resetting the NVRAM doesn't help. I'll try
re-seating the CPU. At present I have no further ideas.

If it's one of those mini's that use the external power brick, it's probably
the brick.

I had a couple of those mini's, one didn't boot/turn on, tried the other
brick, came up fine. Then a month or two later, dead again. I don't think
those were made for more than 10 years of use. No ventilation.

I'm pretty sure the shield has nothing to do with the machine booting.

-bruce