Finally fixed a plasma cutter that stumped me for 2 weeks

Had this Thermal Dynamics unit come in that kept blowing the main fuse after about 10 minutes of use. Checked all the usual stuff, caps, bridge rectifier, even swapped the IGBTs once. Turned out it was a cracked solder joint on the fan speed controller, only showed up when the board got warm. Reflowed it yesterday and ran it for a full hour on a test cut in my shop in Tucson. Felt so dumb it was that simple, but also pretty proud. Anyone else had intermittent faults that only appear after the machine heats up?

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barbaraschmidt6d agoTop Commenter

Buddy of mine chased a ghost in an old lathe for a month, turned out to be a loose wire that only shifted when the motor warmed up, drove him nuts.