Note: groups.io will be down for maintenance on Wednesday, October 5th, starting at 9AM Pacific Time (4PM Wednesday October 5, 2022 UTC), for approximately one hour.
I remember one member had warm cables back last year(?)
His DC power supply +13.8 V DC lug was touching the power supply chassis.
I think the current loop would be from
+13.8 V DC to chassis to protective ground (green wire) to Desktop computer protective ground.
The Desktop pc protective ground is connected to DC ground inside PC
DC ground wire connects CP3/4 and then to the negative lug on 13.8V DC power supply completing the ground loop.
With a DC voltmeter,
I would check voltage from power supply chassis to it's negative 13.8 Volt lug at front and
then chassis to positive lug on front of power supply. Both should be 0 volts.
The member from last year saw -13.8 volts from power supply chassis to negative lug on front of power supply.
That means his +13.8 volt lug on front was shorted to chassis.
As always, I may be wrong again.