I have been finishing up converting a 3DStuffMaker Evolution to something of my own design. I swapped over to a Printrboard and added a heat bed. I have been using my own Marlin firmware for awhile, since before the upgrades at least.
So things are going good on my first attempt. The axes move nicely, the hot end heats up, but my heat bed is reading temps in the 900s. Then when I went to investigate the thermistor wiring I noticed the heatbed was on. I never told it to be on, especially once I realized it was not reading the temps correctly. So I powered down, double checked the wiring, and tried again. When I plug in the power/USB everything seems fine. But as soon as I connect with my host software the heat bed turns on. I can't turn it off until I power down again.
Is there any possible way this is an error in my firmware config? Or does it seem more like a hardware failure?
Oh yeah, I also should mention, that the first time I plugged the power into the board I had the positive/negative reversed. (not my fault, bad info from the vendor [
www.geeetech.com]) I did not have the USB connected at the time. But it did do some funky stuff with my power supply. It made the light go out and seemed to be a dead short for a few seconds.
