12V PSU Healed itself?

[mentaldemise]

I had a 3D Printer PSU go POP. I went to look and see if any caps were screwed and found they were all okay. Underneath the board it looks like there was a short. From what I can see one of the AC in lines to the bridge rectifier jumped to a MOV and blew the track off. The PSU and Printer both worked afterward. What are the chances that blowing the end of the track up fixed the issue?

[mentaldemise]

Thanks. I'm pretty confused still as to what even happened. The printer wasn't printing at the time. I'm not sure why the track would extend so far past the bridge rectifier in the first place. The track that's missing was peeled back to touching the MOV. I assume it's a mov anyway.

[mentaldemise]

I looked again. The part that AC jumped/shorted to is an NTC 5D-11, current limiting thermistor. :/

[mentaldemise]

I'm not sure that's what happened. It looks like the 2 thermistors are connected to the negative output of the bridge rectifier and act as a "fuse" of sorts. It looks like one of the AC tracks actually touched one of the thermistors somehow. I didn't look at it before to know if there was a solder bridge there or a lead sticking out too far.

[Armadillo]

Did  you move the 3D printer before it happened?

[mentaldemise]

No. I had printed like 20 minutes before hand. Was just sitting here and heard a pop, the UPS on the same circuit beeped but didn't trip, and then went to investigate. The 3D printer didn't even turn off or reset the USB connection. I'm wondering if the supply won't be fine if I clean all the carbon off and test it. There could have been a solder bridge under there or something that just exploded. These crappy supplies aren't good at trimming the leads on the bottom. :/