12V from RAMPS to Arduino

Hi there,

I know Arduino gets 12V through RAMPS and in Arduino it goes through 5V regulator and powers on the Arduino.
I know about frying the 5V regulator on Arduino. I have fried mine and replaced it with 7805.
I'm printing from SD.

i just saw Arduino reset itself during warming up. The screen went blank and displayed Marlin boot screen.

So, Is there anything else on the voltage path between RAMPS and Arduino that might black out for a moment and reset Arduino/Marlin?

I just got a new RAMPS and it was a cheapo. I'm suspecting it, but will not rule out PSU problem or Arduino problem.
I'm mentally prepared to replace some parts from the RAMPS, because cheap chinese shit.

Currently my printer is running under load and seems stable.
I'm printing some molds to make silicone damping thingies for heatbed.

It might be a firmware issue? I'm still running RC6.

there are the 5amp polyfuses. these heat up and disconnect when to much current is drawn threw them, then they cool down and conduct again.

I've seen really cheap ones that are just not 'right' If if doubt remove the polyfuse and put a large wire in its place.
Now put a inline fuse into the wire from the power supply to the ramps. (dont run without a fuse)

Thanks,
polyfuses!

Those polyfuses are pain from the experience. I have 2X40mm fans to cool RAMPS, but of course this new RAMPS and new polyfuses might not be happy with it.
I will jump those when/if this problem starts happening during print. Moving the fuses near PSU was my long term plan anyway.

A short anywhere in the 12V supply (e.g. at the heated bed or nozzle heater) can cause the Arduino to reset.