Newbe thinks he burnt up everything

I am new here so be gentle. I have alot of mechanical ability but electronics has not been easy for me.

So for the last two weeks been trying to get started in this hobby of 3d printing. Will probably do a repstrap right from the get go to learn the ropes. I thought i would get the electronics out the way early. So got a arduino mega and a ramps 1.4 and tried learning from there. Got the stepper moving with that Marlin and Pointerface. I noticed the motor smelled and was hot so went to try and dial it down.

So first question is does the pot on the A4988 step stick have a mechanical stop when dialing it down?

I thought I had burnt up my first on so I moved on to the next one and still hot. Measured the voltage and slipped a few times. So I thought i would move to the y axis and after a few lost hours i put in a driver wrong and felt sure i burnt up my ramps board. So ordered two more. Mean while used a l298n on the arduino to move the steppers but could not for the life of me figure out the programing to just make a plotter. So used some cd roms to build a 3 axis unit and had all the steppers moving on the example of one rotation and back. So motors good?

Got the two new ramps in with new A4988. Reprogramed the arduino and connected the ramps and a new driver. Using Marlin that worked for me before and turning the pot ccw a turn then back up 1/4 turn I got nothing.

So asking did I burn the arduino also?

Hope I am not too much over my head.

"So first question is does the pot on the A4988 step stick have a mechanical stop when dialing it down?"
Some do, some do not. Depends on the manufacture

When adjusting pololu modules you should always use a non conducting screwdriver. Shorting it out with a metal screwdriver can cause all sorts of headaches

If you put a driver in wrong, you can easily bridge 12v onto the 5v arduino pins, that is guaranteed to kill the pin and probably more

So if i put the driver (with power connector to the left) in one step to the right off.

Did i burn up the ardunio?

I did run the steppers with that board and L298ns connected to it.

Will I mess up new ramps boards connecting to that ardunio?

Did some hunting around and found a test program for a ramps board. Ran it and all kinds of blinking lights but still not movement on the motors.

Should you be able to read the voltage on the wires going to the motors?

I guess a new board is in order?

One step to the right and you applied 12v from the next position to the gnd pin of the pololu. From there its could go anywhere...

I would suspect this would kill all the mega pins it was connected to.

Last question then, and thank you for your time on all of this, would powering another ramps board with that Arduino destroy the ramps board?
I am just trying to find out just how far down the rabbit hole I have put myself.

Unlikely that you could hurt a ramps with a bad mega. Now in saying that the mosfets are easy to damage, but also easy to replace.

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Using Marlin that worked for me before and turning the pot ccw a turn then back up 1/4 turn I got nothing.

Where did you find such an instruction?

Befrore touching the potmeters, you should measure the Vref. One probe to GND ( eg. servo pin headers ) the other to the center of the potmeter.
If you read a voltage of about 0.4-0.8 volt, you are ready to try the Ramps test.
The adjustment takes only very tiny moves with the screwdriver, depending on the shunt resistors on your stepstick.

Read more here
-Olaf

Test your arduino.
Remove the RAMPS board
Compile and upload in the blink program from the arduino IDE
Does it accept program?
Does the LED blink?

Change the timing parameters
Compile and upload

Does blink rate change?

If all works OK, If not arduino is probably bad (replace arduino)

-- install RAMPS board
Check drivers installed correctly, jumpers in place, wiring
Load RAMP test code see if all is working

DO NOT diddle / fiddle with wiring while powered!
If you are going to adjust driver use non-conductive screwdriver
NO shorting anything

I had to break for the holiday so now i am back to respond to all your helpful comments.
The adjustment I read from is here but now i find i have over read the one turn thing.

[rigidtalk.com]

CAREFULLY turn the pot fully CW (minimum current) then back CCW about 1/4 turn, or enough to make the motor run smoothly

You guys say becareful and use a nonmetal screw driver....but then tell me to measure the voltage with a metal probe. That is kinda funny to me. So me one needs to make a readout that you can plug in and set the voltage with it. Wish i knew how to do that.

I have tried the arduino that is in question now and it loads "programs" fine. I can load to it fine, like the ramps test program. I also run the one stepper rev and back for an entire day.
Now I can load but the motors dont move thru pointerface. I get nothing to the motors even before i go fiddling with them. I do have blinking lights and all so I know something some where is working. The test suppose to run the motors around.

I will be getting a new arduino board tomorrow and going to try it with one of the new ramps boards. I will use one of the drivers i have not touched and see if i get anything. I will also get another arduino, yea over kill but i do plan to build two printers, I hope to see if some of the first things i was using are good with this. So far I am thinking, dangerous I know, that the first arduino and maybe one or two of the drivers will be bad. I amd thinking out puts on the arduino are going to be bad, but i dont know which ones, but the digital ones on the top with the usb on the left are still good since they ran l298n drivers just the other day.

Will be taking you advice into account if I need to change my direction. Thanks for all input I hope to get this right soon and with electronics I am lost. I can design my self out of a paper bag just cant make a fire detector to tell me if I burnt it down.

Quote

CAREFULLY turn the pot fully CW (minimum current) then back CCW about 1/4 turn, or enough to make the motor run smoothly

Nonsense again
Most drivers raise Vref when turning the pot CW. Only DRV8825 work the other way round.
Most potmeters on the drivers don't have a end position. The only way to find "where you are" is probing the Vref.

Some people use a metal screwdriver where the plus-probe is already attached. This way, they can read and adjust at the same time.

Regarding pronterface: The motors do not act normally unless you have "homed" the printer or send G-code commands manually.
From then the response of the motors depend on the firmware settings like steps/unit, max. acceleration.

Depending on your Marlin version, you sometimes have to chose the right controller to make it work. "33" is the magic number...
In configuration.h:

// The following define selects which electronics board you have.
// Please choose the name from boards.h that matches your setup
#ifndef MOTHERBOARD
  #define MOTHERBOARD 33 // BOARD_RAMPS_13_EFB
#endif

-Olaf