Summary
Highlights
The video begins with an examination of a power supply unit (PSU) that exploded, destroying a Microsoft Surface and an external monitor. The PSU is a 15V at 2.58A and 5V at 1.5A unit with a USB port. It's identified as a 'cheap clone' with 'replace AC adapter' branding and a model number DHM 1800, operating at 100-240V input.
The internal components of the PSU show signs of an explosion, with vaporized tracks. The immediate cause is unclear as the fault itself often obliterates evidence. Flashover from the high voltage side to the low voltage side, possibly at the optoisolator pins, is considered a potential cause.
A crucial discovery is made: a small metal tab anchoring a heatsink is found to be making contact with an inductor on a track. This track is identified as a potential initiator of the failure. The inductor, a filter component, had a visible 'splatter' of copper where it rubbed against the aluminum heatsink, causing a short circuit.
This short circuit meant that the low-voltage side, potentially including the USB port and the Surface, became live at mains voltage. When the Surface was connected to a grounded monitor, the mains current found a path to ground through the monitor's signal wires, leading to the destruction of both the Surface and the monitor.
The failure is attributed to poor component placement where the low-voltage side came into contact with the high-voltage mains negative. The heatsink, although meant for heat dissipation, was connected to what appeared to be the ground. Simple fixes, such as adding insulating material or modifying the heatsink to avoid contact, could have prevented this catastrophic failure. This highlights how design oversights, even in seemingly good designs, can lead to dangerous outcomes, affecting both cheap and sometimes even high-quality branded equipment.