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HELP What burned? I Shorted VCC to GND while setting Vref on RAMPS 1.6 with A4988

Posted by ugabuga 
Hey all,
The setup was working. I have RAMPS 1.6 with A4988 steppers which I will be using for a CNC machine I'm building. (The Root3 CNC)
I was trying to set the Vref and my voltmeter probe slipped from the GND pin (I realize now that was a very unsafe way to be measuring the voltage) so it ended up between GND and the next pin which seems to be Vcc.
For a fraction of a second there was a bzzzz and a small puff of smoke.

The screen I have connected to the RAMPS board still turns on although its brightness is all the way up now and the marlin firmware runs but none of the drivers do anything.
I am not sure if I burned something on the RAMPS board or the Arduino 2560.

Visually I cannot tell.
Smell-wise I am thinking it is something on the RAMPS but I have no idea what I should check. If it something I can repair I'd like to try that.

P.s. got a new arduino and ramps in the meantime so I can take my time with this but ideas would be appreciated. Thanks in advance.

p.p.s. The arduino now get quite hot on the side between the USB and power jack connector. The new one doesn't Don't remember if the old one was always like that but doesn't seem normal.
Re: HELP What burned? I Shorted VCC to GND while setting Vref on RAMPS 1.6 with A4988
March 21, 2019 01:04PM
Most likely you just burned the AMS1117 5v regulator on the Arduino Mega. It happens often, e.g. when plugging in the end stop connectors the wrong way.
You can use the search function and find many threads describing the same type of problem, here is one with a photo showing the AMS1117
Thank you. I had a suspicion it might be either a fuse or something related to voltage regulation of some sort, since the Vcc voltage was 5.7V after this happened and that def didn't seem normal.
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