Hey everyone, first time builder here, but an engineer so not a total noob. Problem I am having is on my Prusa i3 rework I am building I turn it on, it boots, and then after about a second it appears to freeze, buttons on the LCD controller don't do anything. Within that second I can navigate menus and such, but then after a second it stops where it's at, no beeps or clicks or anything. Using Marlin firmware 1.1.0, the full graphics smart card, ramps 1.4 clone and a generic Chinese Arduino, wondering if the knock off Arduino might be the issue but thought I would ask the community before I order a "name brand" unit. Motors, extruder fan, and heated bed not wired in yet but everything else is. When it boots up to the information screen, x y and z all say "-----" and it says ERROR: MINTEMP on the bottom. Any ideas or should I just replace the Arduino and go from there?

Thanks!

ERROR: MINTEMP will freeze the whole machine, its a safety measure

This is normally caused by the thermistor wire being broken... or unplugged (or perhaps incorrect thermistor settings in firmware)
Remove the hotend thermistor cable from the pcb, stick your multimeter on ohms and stick the multimeter probes in the thermistor plug, to read the cable and thermistor resistance. Its should read about 100K and 25C.

Also while setting up I would ignore the LCD/SD card and just use a computer with pronterface.. once that’s working go back to the LCD

That's what I was wondering, thanks a million dust!