Power to RAMPS 1.3 or Arduino??

Hi, this might be a silly question to some.. I've finally soldered all parts for the RAMPS and attached to the Arduino. On the RAMPS board, there's 5A and 11A, I know these are power inputs, but what happens with the power input right below it? (the arduino power) is it still necessary? If so, what is the voltage and A?

I bought a cheapo PSU, it has a output chart of:

484W:
20A --- 3.3V
30A --- 5V
30A --- 12V

16W:
0.5A --- 12V
2A --- 5V

I'm not sure which power cable from the PSU I should connect to my RAMPS. The PSU says it has switching mode supply, so I'm guessing any 2 pairs will work, is that right??

Many thanks everyone.

Adrian

You need to take the 12V rail to the 5A connectors on the RAMPS. If you use a heated bed, you need to take a separate pair of wires to the 11A connector as well. Black is ground, yellow is 12V. Leave the power jack on the Mega empty. Normally, you'd supply 12V there, but RAMPS provides power to the Mega.

Many thanks, Andrew.