[kwlug-disc] Strange poweron problem

[CrankyOldBugger]

I have an older machine running Ubuntu 16.04.  I'm having a strange problem
with booting it.

The system is a Intel® Quad-Core Processor J1900 + Micro ATX Motherboard
(one of those motherboard with CPU bundles from Canada Computers).

If I try to power on from cold, the power switch does nothing.  No lights,
no noise, nada.  But if I unplug the USB cable in the back, the power
switch lights up and away we go.  The USB cable in question is the only USB
device attached, and it goes to a USB 3 hub on the desk which currently has
my keyboard and mouse plugged in.  (It doesn't matter if I unplug the cable
from the back of the PC or the hub itself, the results are the same.)

So my question is why would the presence of a USB device stop the system
from powering up, and even more so, why would unplugging the cable cause
the system to suddenly power on?

Sometimes after I do manage to get power on and we go through the POST
Ubuntu will get stuck, but a repeat of power off, power on, unplug USB
cable seems to clear that up.  I don't think this is related to the power
issue but I can't rule that out yet.

While I can live with the frustration of unplugging cables when I'm sitting
there, it makes rebooting from remote login a pain.  I have maybe a one in
three chance of seeing the system come back from remove reboot.

Any ideas?
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