Hi,

Most of the PC Power Supplies sense "Bulk" current for the main forward converter. The individual outputs especially for lower voltages (except for a common regulation node) are not current sensed.

It's likely that the main bulk converter didn't see enough of a change in current sense that it didn't recognize the problem.

Check for the mounting screws and washers shorting traces or planes to the Chassis around the mounting holes. Measure the current if you can of USB devices on the +5V. make sure there is a tie from 3.3V Ground to 5V ground in the system. Are there any shorted (and burned Tantalum capacitors or other Aluminum Electrolytic capacitors (tall cans) that look bulged on the motherboard.

Luckily, the mating connectors and motherboard were compliant to UL or something similar or you might have seen worse damage. The UL make is usually visible on the bare circuit board and will usually be 94V-0 (Flammability Specification) with a unique symbol of the Board Fabricator (not the usually the Assembled Circuit Card Vendor. There may also be a EXXXXX number that matches their UL Registation, sometimes called a Yellow Card. The circuit card assembly with the parts installed is known at the 94V-2 level and all of the parts installed (including your connectors) should meet 94V-1 or 94V-2 minimum. This is where government and industry regulation actually have been valuable. (grin)

I had a UPS that caught fire and you can still have problems, so, you can still have problems, but, it limits the damage.

The pins and the connector are damaged, I would replace them, or replace the motherboard.

Good Luck,

Ross