The most qualified person isn't always the best fault finder.

I've seen it both ways. The degree qualified engineer hits the checklist, finds nothing obvious, swaps parts, power-cycles. Fault's back next week. The other type won't walk away from a fault they haven't found. They'll pull the same connector three times. Come back after dinner and a cheeky beer. Sleep on it. Those are the ones who find: • The pin not quite seated. • The wire clamped on insulation instead of copper. • The intermittent contact that only drops under load. I know who I'd rather have on a breakdown.

Industrial Engineering
Field Service Technician
Maintenance