Hello,
Ok, your situation is a little different from what I first imagined.
Some important points which are not always 100% that way but which can generally be counted on:
* Digital electronics fails the same way as it works - As 1 or 0. Either it works or it does not work. If it is a integrated circuit error (Arduino or Driver) then the error will not be load dependent - It just would not run at all.
As such I do not think the Arduino is the problem.
* You motor should be able to drive just fine at Vref 1 V. If you can move you carriage with your little finger (applying force but without hurting yourself) then you should not have a problem at all. Even it will be able to move much more then that.
Based on the new information I will point to two potential issues:
1) Your power supply is messing things up for you. The easiest way to test this is to try a different power supply. If you do not have a different power supply handy you need to do the following:
a) Try to heat the hotend and bed and see if the voltage drops.
b) Try to put your voltmeter to AC voltage and measure your terminals (on the RAMPS). 0.5V AC would be expected. Several volts indicate we found the problem.
You say your power is staying at 12V but what I am looking for is leaking AC . Leaking AC is when the PSU is actually not working. It allows ripples from the AC to go into the DC and that crashes your drivers. If you put full load on the PSU (heatbed + hotend) then if that is the problem it will crash the PSU (the voltage drops or shutdown)
2) Your RAMPS board might be broken. In particular I am thinking a leaking capacitor. That can give all sorts of erratic behavior.
Ok, your situation is a little different from what I first imagined.
Some important points which are not always 100% that way but which can generally be counted on:
* Digital electronics fails the same way as it works - As 1 or 0. Either it works or it does not work. If it is a integrated circuit error (Arduino or Driver) then the error will not be load dependent - It just would not run at all.
As such I do not think the Arduino is the problem.
* You motor should be able to drive just fine at Vref 1 V. If you can move you carriage with your little finger (applying force but without hurting yourself) then you should not have a problem at all. Even it will be able to move much more then that.
Based on the new information I will point to two potential issues:
1) Your power supply is messing things up for you. The easiest way to test this is to try a different power supply. If you do not have a different power supply handy you need to do the following:
a) Try to heat the hotend and bed and see if the voltage drops.
b) Try to put your voltmeter to AC voltage and measure your terminals (on the RAMPS). 0.5V AC would be expected. Several volts indicate we found the problem.
You say your power is staying at 12V but what I am looking for is leaking AC . Leaking AC is when the PSU is actually not working. It allows ripples from the AC to go into the DC and that crashes your drivers. If you put full load on the PSU (heatbed + hotend) then if that is the problem it will crash the PSU (the voltage drops or shutdown)
2) Your RAMPS board might be broken. In particular I am thinking a leaking capacitor. That can give all sorts of erratic behavior.