Smoke or mist emerging from the PCIe x16 port (note: melted chassis fan wire observed)
Smoke or mist emerging from the PCIe x16 port (note: melted chassis fan wire observed)
You can connect the fans directly to the power supply unit, though they're usually attached to the motherboard or controller for better speed control. Plugging them straight into the PSU makes them run at a steady speed based on the voltage provided. Make sure you match the correct pins, as mismatches can cause issues. You might be able to lower the voltage if it was too high, but overvoltage could have been the problem. A damaged insulation in the wire could also lead to a short circuit. Luckily, the motherboard or PCIe slot appears fine. It seems you were fortunate. If only the wiring was damaged and not the fan itself, simply replace the wire and continue using the fan.