Weirdly specific reboots on a TrigKey S5 that seem to be power supply related.

[spleenharvester]

I have two of these mini PCs: TrigKey S5 with Ryzen 5700U, 32GB RAM, 1TB NVMe SSD, Win11 Pro. They work very well for most uses. They are powered by a HuntKey 19V 4.74A brick with a standard DC5525 tip, which feels decently heavy.

When the brick is connected to the system through a 1 meter DC female-male extension cord (18AWG so decently thick), the system will black screen and reboot when multiple objects are sliced simultaneously in PrusaSlicer. One object is OK. Literally any other activity on the PC is OK. It is just this one specific thing that causes a reboot. I tried running HWInfo on a 20ms interval of >250 parameters and found nothing abnormal recorded at the time of the reboot. No BSoD, nothing logged in event viewer. Even Prime95 and OCCT cannot induce a reboot.

Take the 1 meter extension cord out, problem goes away. Utterly bizarre but completely reproduceable. The same thing happens on both PCs and their power supplies so it is not a unit specific fault. However, if you replace the power supplies with a Lenovo 20V 3.25A brick, the problem goes away, regardless of whether the extension cord is attached. At idle both the Lenovo brick and the Huntkey bricks sit at similar voltage. Haven't checked under load.

I know the simple fix is "replace with a better supply" and I will probably end up doing that, but I am curious as to what is going on here. Is there an LC filter missing in these HuntKey supplies I wonder?

[spleenharvester]

Shoving a 220uF electrolytic low-ESR cap across the DC jack input appears to have fixed this. Not very surprising as the board seems a bit devoid of decoupling caps in that area.

It also seems to have solved an issue I was having where playing audio through the inbuilt speakers on my monitor made the input flicker

[stj]

the original psu is 18v, the lenovo is 20v so volt-drop across the extension will be less noticeable.
barrel jacks arent really rated for more than a couple of amps unless designed for it and usually coloured yellow.
do the connectors get warm?

[spleenharvester]

the original psu is 18v, the lenovo is 20v so volt-drop across the extension will be less noticeable.
barrel jacks arent really rated for more than a couple of amps unless designed for it and usually coloured yellow.
do the connectors get warm?

Nah connectors don't get warm at all, even after Prime95. As an aside, barrels seem to vary in quality - I have one on 18AWG cable on my ebike that carries 210W and only gets slightly warm - tried a different cable and it melted lol

[spleenharvester]

It's started doing it again, but with different triggers. This time opening Excel seems to set it off. Not really sure what to try now, RC filter possibly?

[truclacicr]

Maybe the supply doesn't handle big load changes very well. Can you see what happens if you switch on an additional 1A or 2A load while the system is idling? For example, a bank of dummy load resistors of sufficient wattage might provoke the fault. Alternatively, the element in a 2200W 240V electric jug has a resistance of 26 ohms. That would draw about 0.8A from 20V.