Preheat test damaged the board - ramps 1.4 (1 reply)

Hello everyone,

I'm building a custom 3d printer using ramps 1.4 board.
Thanks to reprap community, I've completed to run motors and endstoppers very quickly.

I have connected the mk3 heatbed to D8 and mk8 hotend to D10.
They both have 100K NTCs.
Hotend thermistor was connected to T0, and hotbed thermistor was connected to T1.
In the configuration file, hotend sensor setting was 1, sensor0.
Hotbed sensor setting was 0.

When I chose preheat from lcd menu, a red led on ramps was on for about 5 seconds then I lost view from lcd screen.

I checked the regulator on arduino and middle pin gives around 3 volts. Now I will change the regulator but what is my problem?

NTCs and heater don't have polarity.
I was testing for pla.

My endstoppers may be active while I was making preheat test, does this may be the reason?

Thanks.