Fried mega?

Hi,
Sorry my english isn't very good.
Got a shortcircuit on my prusa. The 2 wires of the heater cartridge went naked and touched each other. They went red. The thermistance of my extruder died in the process.
Now my heat bed doesn't heat anymore but the thermistance works fine. The extruder stepper motor doesn't get command neither but it works fine if i switch it with one of the axis stepper motors...
Everything else works fine.
I replaced the RAMPS but nothing changed.
So i wonder if my mega could have partially fried?
Does anybody have an idea on how to test it?

Thx

Edited 4 time(s). Last edit at 10/11/2016 04:12AM by T3D.

It's not likely that your Mega got fried, but possible. Especially if you can still communicate with it from a PC. The RAMPS would be much more likely.

Probably the extruder is being disabled by software because the software knows the hot-end isn't up to temperature? Possibly the software is also disabling your nozzle heater because it knows the thermistor is bad? I assume you replaced the heater cartridge that shorted?

1. Try switching the heated bed and hot-end thermistors. Change the connections at the RAMPS, so any wiring faults don't confuse things.
2. Check that your 12V supply is OK... check the voltage with a load on it (e.g. with heated bed or nozzle on).
3. Check all your connections and make sure there's no broken wires. (Seems to me that if I change a board, I manage to break or disconnect a wire).
4. Does an axis stepper work when plugged in in place of the extruder motor? (Change the connections at the RAMPS, so any wiring faults don't confuse things).
5. Connect your nozzle heater directly to the 12V supply as a test... does it heat? Don't forget to disconnect it!
6. Re-flash the Mega.

BTW, your English is excellent!

Edited 1 time(s). Last edit at 10/11/2016 08:11PM by frankvdh.