Ramps started smoking?

Hello, yesterday I got my stepper motors and I decided to test them, so I wired the ramps like this: I put all the DRV8825 on the right place, put only one stepper motor on Y axis, one endstop for Ymin, and the LCD connected, on the terminal blocks I had only the 12V 5A input wired, after messing around with the motor movement and pressed auto home, it went to the endstop as expected and about 5 seconds later I started to smell burning and there was smoke coming out between the arduino and the ramps 1.4, I immediately turned it off and after it cooled down it was working again, I read something online about tuning the Vref to limit the current on the drivers and when I went to check it, I put the black pointer on the GND and the red one on the potentiometer while the printer was turned on but I always got a 0 reading on all of the drivers, what could it be?

Edit: Now I noticed my LCD screen only works when plugged on pc, if its only on the power supply it wont work

Edited 1 time(s). Last edit at 01/08/2018 03:31PM by matheustorres.

nope...not vref

You have endstops wired backwards, then it triggered it shorted 5v to gnd and smoked the 5v voltage regulator on the mega

Well that would be my guess...

now if you have the mega pluged into usb it will use 5v from usb power, but without usb I suspect you will not have 5v any more.

My endstop has 3 wires, + - and signal, I heard that there are some problems when connecting to the +, should I remove the + wire and will it work fine?

By the way it was not connected to the USB, it was plugged but not plugged in to the PC, all of the power was coming only from the 5A 12V input.

About the vref, was I measuring it wrong?

Edited 1 time(s). Last edit at 01/08/2018 08:10AM by matheustorres.

Semi off-topic
Oh. my. god. I just fried 2 arduinos last night too!

I'm guessing I plugged the stepper drives in incorrectly (I was working in a very tight space, adjusting the microstepping, and changing drivers), and at some point, my arduino started smoking.

I didn't diagnose the problem before I started tearing things apart, but I'm assuming my stepper drivers were off a pin... Now I need to play around and see which ones I fried... If not all of them...

Turns out that the 5v regulator on my arduino boards (lol both of them) are toast. I ordered some AMS1117 5v regs off of ebay, and plan to try and replace them, and pray that the amtel chips are still functional. Right now the Vreg outputs around 8-9v depending on which fried board we're talking about, but yeah appears to fine when plugged in via USB.


Anyway, back on topic, it sorta sounds like your endstop was wired weird... do you have a picture of your wiring job by any chance we could take a look at?

By the way, the arduino got fried, today I bought a new one and it is all working fine. Now that I think about it, it started smoking when the endstop got triggered so probably it was the problem that Dust suggested, about the wiring, I probably plugged in the wrong way, insted of S - +, I did + - S, if you want I can send the picture but only tomorrow, let me know