Short on stepper now other problems

I shorted the extruder A4998 stepper when I was trying to measure voltage. There was a burning smell coming from the board. Luckily I had a spare. Now I'm having some weird problems that I need help with. When I'm connected to my computer, all is well. I can see the LCD. Manual controls work fine. Sending prints works fine. All is good. When I disconnect from the computer to use the LCD, I didn't see any text at first. I had to jack up the contrast. That is not a viable solution as I have to mess with the contrast every time I connect to the computer. When I move my X, Y, and Extruder from the LCD, it works fine. When I move my Z, it hangs as if there is not enough voltage. I don't have that problem when plugged into the computer. Did I also possibly fry my RAMPS board or Arduino board? If not, what could be the issue causing contrast and Z axis motors to be funky when not connected to a computer?

You may have burned up the 5V regulator- a common problem when you connect an LCD module to Arduino/RAMPS. Get out your volt meter and check it.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

So that would be an Arduino issue I take it. Probably easier to just buy a new board since it works now with a computer, and I'm going to have to remove everything.

So I pulled off the Arduino board, and there is a fried smell coming off of the RAMPS board after trying to do a print. So something else may have shorted out, because I cannot get Slicer to show the print preview, and running a print starts the machine but no filament comes out. This is when hooked up to the computer. Not sure if that smell means the RAMPS is fried. So plugging the Arduino board to a 12v power supply from something else, I measured the voltage from the 5v regulator. The power in side is showing 11.45 volts. The output was 4 volts. With the board plugged in for a few more minutes, it dropped to below 3 volts. The L and ON lights were both on. The L light went off when the voltage dropped to 3 volts. So is this an Arduino voltage issue? I'm assuming the voltage should be at 5 volts not 4 or 3. Is it possible both are fried with the smell coming from the RAMPS board?

Yes it should be 5v.

It is possible you have damaged both... depending on what you touch, you can short 12v to 5v, and thats very bad.
But it sounds more like you shorted 5v to GND and damaged the regulater...

Can't comment to the smell, could be a few things.
The mosfets burning out for eg, or the bed plug melting from not being screwed down hard or being a inferior part (not rated for the current)


You need to identity what what is making the smell.

I got the new boards today. One of the mosfets is blown. Lesson learned not to test volts with main power plugged in. USB should be plenty of volts for these parts.