Perhaps to start over
Find a known good Arduino Mega (test it with example sketches)
Mount your best RAMPS on it with good stepper drivers, jumpers in the right place
Test your power supply measure under a load.
Check all connectors and connections, anything suspect measure for continuity
may be a good time for all cables to be 4 pair shielded cables even end stops
DO NOT fiddle with stepper wires while RAMPS is powered -- good way to fry drivers
With all that
Load RAMPS test code
[reprap.org]
It switches on and off all the MOSFET outputs (this will make the leds blink) just be careful not to have the heated bed and extruder heater connected unless you want to heat them. Plus it will move back and forth all the stepper motors connected.
If that works OK
Configure and load Marlin / repetier firmware
Print away be happy
:S
Find a known good Arduino Mega (test it with example sketches)
Mount your best RAMPS on it with good stepper drivers, jumpers in the right place
Test your power supply measure under a load.
Check all connectors and connections, anything suspect measure for continuity
may be a good time for all cables to be 4 pair shielded cables even end stops
DO NOT fiddle with stepper wires while RAMPS is powered -- good way to fry drivers
With all that
Load RAMPS test code
[reprap.org]
It switches on and off all the MOSFET outputs (this will make the leds blink) just be careful not to have the heated bed and extruder heater connected unless you want to heat them. Plus it will move back and forth all the stepper motors connected.
If that works OK
Configure and load Marlin / repetier firmware
Print away be happy
:S