I was working with my FRDM-KL25Z board, and now it won't power up.

My incoming power is 24V, and I'm using a switching supply (24V05) to convert that to 5 volts. I was working on the circuit, and accidentally connected the ground while the power was on. There was a small spark, and now my MBED seems to be dead. It won't power on, and when I connect it to either 5V externally or via USB, the 3.3V regulator gets quite warm.

Any ideas where I should start in trying to revive this board? I've already tried swapping the 3.3V regulator with a known good one, but that didn't seem to help.

Thanks for any advice!

Hello,

I once soldered a jlink connector, I bridged GND with VCC without even noticing (one tiny thread connected those 2 pins).

There are few diodes (U8, D2, and D5). I destroyed U8, it's right next to the usb connector. I just removed it in order to make it work again. Measure inputs on those diodes.

Regards,
0xc0170

It wasn't a short, and I'm sad to say it happened more than once....I have two dead boards here, from the exact same cause.

both boards had same damage?