Fried my monotronics

When I connected my opto endstops to my monotronics board, the monotronics board died. Or rather, I connected the opto endstops, and then the USB cable to my computer, and the LEDs lit up, and then immediately went dark. SInce that it's dead. Maybe there was a short in one of the opto endstops, but I've gone over it with a magnifying glass, but can't find anything. But I'll have to assume that there was one (either in my soldering or other hardware), or that I connected them wrong, which is bad, but I don't think I did.

So now I need to figure out what's fried. Any ideas on what's most likely, and where to start looking? I had only connected the USB when this happened (though I stupidly connected the main power as well afterwards). Poking around on the board I've been identified the major components as:

- FT232RL USB-to-RS232 chip
- Atmel MEGA644
- 4x A3982SLB-T motor drivers
- L7805CV voltage regulator
- Some sort of transistor marked "738 20 N6L" (googling for "738 transistor" gives some hits)

So, which is most likely to be dead? The voltage regulator?

Cheers, Ketil

I assume you've unplugged the opto's and motors and tried it stand alone? (Remembering to switch it off first!)

V-Reg should be easy to check with a multimeter

Thanks for the tip. I tried the #reprap channel on irc as well, and got the same suggestion, and I've given it a try.

Now the monotronics board wakes when I connect USB, but nothing happens when I connect power. Perhaps I've burned my PSU. Will have to check some more when I get a multimeter.

Cheers, Ketil

Checked some more. Found a matching PSU and tried that instead, with no luck. So since there is some life with the USB cable connected, and none with any PSU I've tried, I'm guessing the regulator is fried. And fortunately, since it seems to work as expected with only USB connected, there are several bits still working!

Thanks for the help.