I'm having a huge pain trying to fix my Da Vinci. I've run my Da Vinci about 100 hours in the last month, with no issues whatsoever...until i went on vacation for the 4th of July. Unplugged my Da Vinci 1.0, left for 4 days, came back, and the X-Axis is completely screwy. At first, i noticed the thing immediately skew left, so i replaced the endstop. Then the wiring to the endstop. Then on advice from a previous post, i put a 24" box fan in front of the door blowing in, and only then did it work, but i have no idea why, because since then, i have put heatsinks on both the X and Y stepper driver, attempted to blow air on the stepper driver from multiple angles using a 6" fan, blown cold air over the stepper driver with said fan, with and without heatsink, greased the X and Y axis rods, checked the input power...I'm really not sure what to do. It seems like the x-axis stepper motor is stalling or something, it seems to just start traveling the wrong direction at random, corresponding to a grinding/bumping noise. Does anyone have a suggestion?

I was having a similar problem and after first rerouting the cables and putting in the cable chain, it was fine for a while then started happening again. The only difference this time was I had Repetier running on it.

I've noticed that if I drop my temps down on the bed and extruders, it works just fine without a problem.

I changed the stepper drivers on the board, with the steppers that where on my Ramps. had to solder the pins out at one site.
Then i could adjust the current to lower normal levels.
Result: Cooler motors and quiter operation.
This is something that you can do as an experiment. Costs you a set of pins, and 10 minutes to solder. Can do it for the 1 axe that is problematic.
For now, i keep the Davinci motherbord, with the ramps drivers (in my case on X and Y axes)

His unit is a 1.0A it does  not have the driver in sockets. They are a chip soldered directly to the main board. There is no place on the mainboard to solder a pot to because it uses digital control. So even if he had the equipment to remove the actual chip from a stepdriver or other carrier he still would not be able to control current simply by mounting a new driver.

Speaking of, on the thermistor for the Da Vinci 1.0 hotend, can I pull the thermistor values directly off the ribbon cable, or do i need to run a separate wire for the thermistor to the RAMPS board?

Sounds Like you have the same issue I did with my 1.0 and the driver is also shot. Unfortunately on a 1.0A, unlike the 1.0 which has the drivers in sockets yours are soldered to the board so there is no way to swap. The best you can do is contact one of the several guys on here parting out their Da Vinci's and see if the have a 1.0A board. XYZ does not sell the boards, but you can also check Ebay as I see them on there sometimes.

Your other option is do what myslef and several others did and swap out the mainboard for a RAMPS 1.4 and LCD. Its not easy but it gives you a great insight to the printer and how it works.

I assure you, i am not ignoring your advice. I am running a Da Vinci 1.0a serial beggining 3F10A. I do not have the luxury of swapping out stepper drivers, as they are a part of the board, or i would have swapped the X and Z driver long ago.

I swapped out my X-Axis steppers, same issue. I have a heatsink on the X and Y axis drivers, and a 6" fan blowing on the whole mboard, still not sure what is causing this.

Can I ask you why you are not taking our advice and accepting that the motor is bad?

Again you said when you had a fan blowing into the print area as I recommended that it worked and completed the print. That would point to a motor, not a driver.

No you say you have swapped drivers and even force cool the controller and it still happens. Again pointing to a bad motor.

They do go bad and it common for them to do so in these machines. Especially true of XYZ machines where they are over driven.

A motor has even been offered to you because we all know they go bad.