POS-Mainboard-Ausfall: Kein Strom, kein POST, geblähte Kondensatoren — diagnostizieren vor dem Tausch

“The motherboard is dead” is the most over-diagnosed fault in POS repair. A dead power supply, a flat coin battery, or unseated RAM all imitate a dead board — and they’re far cheaper to fix. Before you replace a mainboard, prove it’s actually the board. Triage in this order:

The fastest mainboard diagnosis is your eyes. Bad capacitors and physical damage have unmistakable signatures:

Scan the whole board for domed or leaking capacitors, scorch/burn marks, corrosion (often from spills or damp), and broken or melted connectors. Any one of these can cause random crashes, POST failures, or a board that won’t boot at all.

Match the symptom — but note how many overlap with cheaper parts, which is exactly why you isolate before condemning the board:

Work the sequence with the unit powered off between steps. Each step proves a cheaper part good (or bad) before the board takes the blame:

One symptom is so commonly mistaken for a dying board that it deserves its own note: losing the time and settings.

When the board really is at fault, the choice is repair or replace. Match it to the damage and your capability:

Browse boards in our mainboards category, related components in terminal repair parts, and supplies in power supplies. If the terminal simply won’t boot, start with the broader won’t-boot guide; to clear the power supply first, the power-supply diagnosis guide; and for choosing genuine vs aftermarket vs refurbished, our parts-tier guide. Send us the board model or terminal and we’ll match a tested replacement.