Ramps Endstop Short

I apologize in advance if this topic has already been posted, I couldn't find anything that really applied to my situation.

So I have a folgertech prusa i3 that has been working great, but I switched out one of the endstops while it was on and I presume that I shorted some of contacts with my fingers (dumb dumb, I should have unplugged the machine but I was to lazy). Upon brushing the contacts the screen went entirely white, I tried to reset, and then tried to reload marlin on the mega, but avrdude could not locate the mega and device manager was showing that an unknown device was plugged into the com.

I removed the ramps board from the mega and tried communication again and it worked! but then upon putting the ramps board on again it failed. interestingly I found there to be a slight image on the display screen when I reassembled it, and upon turning the pot I was able to see that the normal status display was being displayed and I scroll through the menus. But I could not control the motors or access the SD card.

Does anybody know what exactly I may have shorted with the endstop? it seems that arduino is working but not the ramps board, is this true? Looking at the ramps schematics it looks like the endstop current just goes right back into the mega so how could it harm the ramps? Do I need to replace the ramps, the mega, or both?

Thanks so much!

You have damaged the voltage regulator on the mega

If you power the mega from a usb cable it doesn’t use the voltage regulator

If you power the mega from the DC jack or the vin pin it goes via the voltage regular , the ramps applies 12v via D1 to the mega vin pin.

Plug power into the mega dc jack (7-12V) and check that the 5v pins have 5v

Oh, thanks Dust!
Yeah i'm getting 6+ volts when going through the dc jack.

Is there anyway to get around this? Could I bend the vin pin out of the way and power the mega via usb? I think that would adversely affect the ground but I don't know.

Just cut D1 out of the ramps (one end is enough), then the mega is powered by USB only. GNDS are already joined



Edited 1 time(s). Last edit at 02/08/2016 05:22PM by Dust.

Oh interesting, I found a voltage regulator I had lying around and jerry rigged it in, back up and running now. Sounds like the voltage regulators get burnt out pretty often though, so i'll keep this in my back pocket. Thank you!

Quote
cpayne
Oh interesting, I found a voltage regulator I had lying around and jerry rigged it in, back up and running now. Sounds like the voltage regulators get burnt out pretty often though, so i'll keep this in my back pocket. Thank you!

If they brun out often, then somerhing else is going on. Been using a couple of ramps for multiple builds the past year, and never had such problems.

Always remove ALL power when doing any rewirering and you should be fine.

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