Repair an industrial Atom Mini-PC with a faulty tantalum capacitor

I’ve been using a small Chinese mini-PC as a Proxmox Backup Server for quite some time.

Nothing fancy:

• 8 GB SO-DIMM RAM
• M.2 SATA SSD
• Intel Atom CPU
• Low power consumption, always on

Until one day… I found it turned off. No LEDs, no signs of life at all. Pressing the power button did absolutely nothing.

At first, I suspected the usual suspects:

• External power supply
• Power button
• RAM or SSD failure

The power supply was fine, and disconnecting all peripherals changed nothing. The board was simply dead.

After opening the case, I did a quick visual inspection. No burnt components, no obvious damage, no blown electrolytic capacitors.

I powered the board briefly and scanned it using a thermal camera, almost immediately, one component stood out: a small tantalum capacitor was getting hot very quickly.

Tantalum capacitors are known to fail short-circuit. When they do, they can pull down the entire power supply and prevent the system from starting at all.

I removed the faulty tantalum capacitor and replaced it with a new capacitor of the same value and a slightly higher voltage rating, cause I was able to find a 6.3V one.

Before reassembling everything, I powered the board again and checked it, pressed the power button and the BIOS appeared, Proxmox booted normally, and the server has been running stable ever since.

Notes

• read risk disclaimer
• excuse my bad english