Had a power supply board let out the magic smoke on a 55 inch TV yesterday...

It was a pretty normal repair job, a Samsung with no backlight. I had the back off and was checking the usual caps and fuses. I had my meter on the main filter cap, just checking voltage, and I must have slipped... my probe touched two points it shouldn't have. There was a loud pop and a puff of gray smoke from near the PWM controller chip. My heart just sank. I shut everything down right away. The board had a clear scorch mark on a tiny surface mount resistor now. I spent the next two hours carefully cleaning the area and trying to find a schematic to see what that part even was. It's fixed now, but man, that was a dumb, expensive mistake. Anyone have a good trick for keeping probe tips steady on those tiny board points?

3 comments

3 Comments

reese_chen27d ago

Man, that "loud pop" feeling is the worst. I started using those little spring-loaded hook probes for tight spots, they grip on and you don't have to hold them. It's saved me from a few more of those heart-sinking moments for sure.

spencerh9527d ago

Tried using a bit of poster tack to hold the probe in place once. It sounds silly, but it gives you a third hand for those shaky moments. Saved a board last week with that trick.

corad8412d ago

That poster tack trick is clever for a stable test point. When you used it, did you find any residue left behind on the probe tip or the board after you pulled it off? I've had cheap tack leave a greasy film on things before.