I have one of the first Metal Pluses, had nothing but issues with it over the heated bed and more or less gave up on it. After more than a year hiatus I started working with it again and upgraded the heated bed to use an A/C powered keenovo heated bed. Can get up to temp in 1 minute.
Things were working mostly ok until I tried upgrading the firmware to get more than a 3 point calibration and I think that is where the problems started, I lost my old M909 settings and the Y-axis motor started skipping. Managed to narrow down that it was in fact overheating. Thought it was heated bed related, so I tried with that turned off, but the Y motor still overheats, tried swapping the X & Y and the Y-stepper and it still overheats. I finally was able to print a 0.5 in single wall test print when I lowered the Y-stepper motor down to 30% current. I also tried lubricating the slide yesterday, and loosening the Y-stepper belt. I tried printing 6 cubes and it failed, almost all steppers were hot in this case. I'm going to try lowering all the motors to 30% and trying again tonight.
Should I have to turn down the current that low to keep it from overheating? I also put back the original firmware just to rule that out of the equation.