Mega 2560 V+ short to RAMPS 1.4 GND

I am running a Mega 2560 / RAMPS 1.4 stack using a 24V setup:
1. Remove D1, power the mega via the 2.1mm center-positive DC jack, The recommended range is 7 to 12 volts.
I have cut D1, and the 12V is produced using a 24-12V buck converter.

While the two boards are connected there is continuity from the Mega DC jack V+ to RAMPS GND. This is with nothing else connected; just a large sink on the Mega which does not touch anything. Is there any way of knowing which components are causing this? Is there a higher chance of it being one of the two boards?

Since I discovered this by nearly popping the 3A buck converter with everything plugged in, I guess the Mega is fried? But the [potential culprit] RAMPS lives on?

I suppose I might want to order both state-side. Has anyone else had a similar experience?

EDIT: My friend gave me a MKS Gen 1.4 and the printer runs on it. I'm using the LCD that came in the same kit as the boards though... the thing doesn't drive correctly and has a pixel offset; barely legible yet hideous. Bad electronics...

Edited 1 time(s). Last edit at 02/08/2020 12:33AM by ders.

The reason I added a DC to DC buck converter, was that in order to allow for 24 volts. I had to replace the AMS1117-5.0 on the Arduino as it had died earlier.
The AMS1117-5.0 component only allows for a max input voltage of 15volt and a current draw of 1 amp, if shorted or higher voltage was applied then this part fried.

More in my post about updating to 24V for my MPCNC Arduino Mega and Ramps 1.6 boards below.

[reprap.org]

[reprap.org]

I added the DC to DC buck converters for added current to the Arduino Mega/Ramps 1.6 and eliminate the cheaper AMS1117-5.0.

Edited 7 time(s). Last edit at 02/08/2020 08:36AM by Roberts_Clif.

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Computer Programmer / Electronics Technician

If it's a cheap mega board, use 10v roughly. 12v causes heat issues and to blow the regulator. I believe that continuity is normal. There has to, at least in all of my custom arduino work, be ground continuity to make the digital rise/fall to work correctly, so this may be normal