12v overheating (voltage problem)

Hi everyone! i recently bought an Arduino Mega 2560 with a Ramps, an LCD (with a kit) and a 30A@12V PSU. The problem is, when i was doing some testing with my new "toys", a screw fell from my table and touched some pins from the LCD panel. Now the whole kit runs well with only USB connection, but when i connect it USB+PSU or only PSU it REALLY overheats (it burned a little bit my finger) and the LCD just keeps white. I did some measures with my multimeter and my Mega 2560 and, when only connected to USB, all the Power Out pins have their respective voltage (3.3+GND=3.3, 5+GND=4.80-5, VIN+GND=5) but when i connect it to the PSU it gives higher readings in the 5V line (above 9.5V). My questions are, Is the voltage regulator ruined? Where is EXACTLY located the voltage regulator? Is it easy to change it and how do i change it? I am a little bit desperate because it's a shared project :drooling_face: Thanks for the help you can give me :)

In some ways it is easy to replace it. As smd components go, it is an easier form to remove.

But, and a big but, when I was yanking the one off my board. Not literally! every single pad ripped up with the corresponding leg. Sucked.

Why not pop the VReg off and convert to 5v permanently on the plug input? I did that to power the board off portable usb batteries and it is as happy as a pig in poop.

Andrew

Thanks for the replies! I can't convert it to 5V permanently because i need the two voltages (it goes attached to the RAMPS and some components need 12v and others 5v). I have already taken off the voltage regulator so now i need to attach a new one of similar (or better) features and hope that everything works fine. i'll keep you informed, if you have some other solution (besides buying a new one :P) please let me know and i'll try it. :)