Oh my, that is quite the burnt trace you have there, I assume the board was not touching the case anywhere .. it looks like the board has grounded out on the case.

This can also happen when someone shorted a supply voltage somewhere on the mainboard - by dropping a screwdriver or some piece of metal. Smaller traces burn before the PSU shuts down.

The 4 screws are plastic or metallic ?

Metal screws with no isolating washers between them and the PCB?

majestyk wrote on 2022-07-16, 07:11:

Metal screws with no isolating washers between them and the PCB?

No there are isolating washers.

I think when my soldering skills improve I will attempt to repair this. I think if I'm tedious and careful I can use copper foil tape and fix this.

Now that I think about it, I bet that screw on the top left maybe shorted on the chassis somehow. Maybe touched when on and caused the short.

Sly_Botts wrote on 2022-07-17, 01:31:

Now that I think about it, I bet that screw on the top left maybe shorted on the chassis somehow. Maybe touched when on and caused the short.

Could be ! Maybe the painted coating was not enough on those black screws. Those do not look like original Slot-1 retention parts but aftermarket.
Most of my Slot-1 boards use a Nylon/plastic fastener for the original socket retention part and some with brass screws but they are built different with insulated plastic inserts.
They make those red fiber washers for using on the top of boards but maybe should have been used on the bottom for these screws too... just thinking out loud... 😀

Horun wrote on 2022-07-17, 02:46:

Could be ! Maybe the painted coating was not enough on those black screws. Those do not look like original Slot-1 retention par […]
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Sly_Botts wrote on 2022-07-17, 01:31:

Now that I think about it, I bet that screw on the top left maybe shorted on the chassis somehow. Maybe touched when on and caused the short.

Could be ! Maybe the painted coating was not enough on those black screws. Those do not look like original Slot-1 retention parts but aftermarket.
Most of my Slot-1 boards use a Nylon/plastic fastener for the original socket retention part and some with brass screws but they are built different with insulated plastic inserts.
They make those red fiber washers for using on the top of boards but maybe should have been used on the bottom for these screws too... just thinking out loud... 😀

Possibly, though an Epox / slot 1 image seach on UR suggests that the black screws may have been used on at least some of these boards. As a comparison, my Supermico slot 1 boards (all I believe wirh original retention brackets) use an 'identical' part - black metal screws with a separate but captive black plastic insulating washer.

Trace repair complete! I used enamel coated magnetic wire. BNTECHGO 30 AWG Magnet Wire - Enameled Copper Wire - 0.0098" Diameter - Natural Temperature Rating 155℃

Southbridge is now getting power. Chassis fan port working again. Fan on AGP card working again but no picture. I think I will try this with a PCI card when it comes in the mail. If it posts fine, I will know something is up with the AGP slot.

So was it the slot screw?

Sphere478 wrote on 2022-07-30, 05:36:

So was it the slot screw?

No there is plastic between the Screw and pcb.

I see two unconneted vias under the burned trace.