When I try to print, the heated bed will not heat up. Specifically, during the step when the printer prepares to print, moves the nozzle down and to the left, then heats up to the specified temperature for the nozzle and bed, the nozzle will heat up and the bed will not.
If, before I start a print, I set the bed temperature to the desired amount manually, then start a print, the heated bed will cool to about 50 degrees by the time the nozzle heats up.
If, before I start a print, I set the nozzle temperature, then the bed temp, then start the print - it starts and stays at 70 degrees.