Guides

Board won't power on — first checks

Contributed by CircuitScope · Added 05 Oct 2026 · 2 views

A logical order for chasing a dead board before you reach for the hot air.

Before assuming the worst, work through the power chain in order.

  1. Test the supply. Measure the adapter/PSU output on the meter — is it actually delivering the rated voltage under load?
  2. Check the fuse and input protection. Many boards have a small fuse or polyfuse right after the power jack.
  3. Look for shorts on the rails. With power off, measure resistance from each main rail to ground. A near-zero reading means a shorted cap, IC or a stray solder bridge.
  4. Inspect for damage. Corrosion, burnt components, cracked solder joints and liquid residue are all visible clues.
  5. Bring it up on a bench supply with current limiting so a short doesn't cook anything while you probe.