Firmware for RAMPS without diode?

HI. I have already lost an Arduino. So I want to remove the D1 diode in my RAMPS 1.4 to protect the Arduino Mega from over voltage.Can  I run the printer powering the arduino from my laptop's usb? Also do I need to change anything in the firmware for this? I am using the sprinter firmware. 

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seandogue2 years ago

oooooooh. So you connected an external power supply to the ramps without removing the diode which delivers power to the board from either an external supply or from the USB but not both. Yeah, you should never have connected the 12V supply without first removing the jumper.

Although I know enough never to do such a thing, since I'm not an arduino expert and really don't have time for handing holding, I'm going to refer you to those who are


topic is "Ramps and D! diode" Reprap is a great source of details for those who use arduinos 'specially when it comes to 3D printing.

Thanks Steve, for teasing the critically missing info out

SowmenD (author)  seandogue2 years ago

Thanks a lot :)

iceng2 years ago

How does removing a diode protect any better then removing a wire ?

SowmenD (author)  iceng2 years ago

That's what it says in the RAMPS guide. It says removing the D1 diode will stop powering the arduino and as a result it can support more than 12V. I need to know wether this is ok and do i need to edit the firmware or not.

fwiw, I believe the external supply can be anything from around 8 or 9 VDC to ~16 VDC, although I'd recommend checking with the specs and with that link I passed to you before listening to me on that. as I said, not an "arduino expert" nor do I have time (or to be honest, patience) for more than passing comments. In fact, it pays to always use authoritative documentation over the word of anyone you meet in the wild unless you cannot find any such documentation and are foreced to believe what you hear..

You're welcome. Great link find there too. Saves me digging it out ;-)

I don't see a wiring diagram for what you did in your previous question. It looks to me you exceeded or reversed the input voltage - you probably fried the processor through the motor drive pins, not the supply rails, because they can handle 35 volts or so, for a short time

Moral:Don't overvoltage the board in the first place ! It has a 12V limit for a reason !

SowmenD (author)  steveastrouk2 years ago

I don't even know how it was over voltaged. I supplied power via an ATX power supply with the 12v line. But still my arduino busted and also a pololu driver was burnt out. So now i got a replacement and want to make sure that my arduino won't burn out again. So should i do it? and also about the firmware?

Before I comment, draw me/us a schematic of what you DID and I'll tell you how to make sure it doesn't ever happen again. How's that ?
SowmenD (author)  steveastrouk2 years ago

I already posted about this problem here.
I would really like to know about that D1 diode. In the RAMPS wiki it says i can take it out and have to supply power to the arduino separately. I want to know if i need to change anything in the firmware. and also if only the USB is enough to power the arduino.