Hi,
If the ramps works fine (no red led lightened permanently), it's ok.
If there's a permanent led, change the corresponding transistor.
Be sure your hotend parts are not twisted or damaged by the overheat.
Be sure to secure the heat resistor and the thermistor to the hotend with Kapton tape.
8.5A seems light to me for a 3D printer. Mine is 25A.
With the 1.4 Ramps board, you can power both your boards with the 12V on the Ramps only.
If you print from your computer you'd rather plug you USB cable after turning the 12V PSU on.
I recommand to print from a SD card without connecting the computer.
The print is more fluent and faster this way, and there's no computer side issues.
++JM
Edited 1 time(s). Last edit at 08/25/2015 07:27AM by J-Max.