Bought a $60 thermal camera off Amazon to find a short on a motherboard, best tool I own now
Client brought in an HP that would not power on at all and I was about to quote a full board replacement. Pulled the thermal cam out, powered it up, and saw one tiny cap glowing hot within 30 seconds, swapped it for a $2 part and the thing booted. What cheap tool ended up being way more useful than you expected on the bench?