LCD and extruder heater died

I've got a modded Davinci 1.0, and I was trying to load new filament (and thus probably bumping wires) and suddenly my LCD went dark, and the extruder no longer heats. 

• I tried shining a light into the LCD to see if it was just the backlight, and I couldn't detect any text

• The buttons near the LCD beep and act like they are working, as far as I can remember menu options

• Connecting to it via Repetier-Host, I can turn the hot-bed on/off and control all 4 servos.

• However, if I try to turn on the extruder heat in Repetier-Host, it acts like it knows it can't.  The button changes to the On icon, but the temperature graph still shows a desired temperature of OFF.

My intuition says that I either:

• Blew a fuse, (or fried something electronic that wasn't fused)

• My power supply might have partially failed.  (IOW, maybe 1 of the 3.3/5/12V lines aren't regulating, and maybe that line powers both the LCD and whatever controls the Extruder Heater MOSFET)

• Something went wrong in the firmware and might be able to be debugged?  Is it possible to attach a debugger to the board either via USB or serial?  (I can solder on a header if needed.)

My purpose for this post is two-sided:  If this is fixable, I'd like to fix it.  If this a sign the board itself is now fried, I'd rather not waste time debugging, and I'll replace the electronics with RAMPS, and upgrade to a 2nd extruder, like I've wanted to for a while.

Thoughts?  I'll be tearing into it more thoroughly in the next few days.