HP LaserJet 8100 and 8150 series printers 50.1 error code

A 50.1 error indicates a low fuser temperature.  This error occurs when the fuser is not able to heat to its operating temperature.  Here are the possible causes in order of significance:

1        The low voltage power supply has failed.  Circuitry in the low voltage power supply has malfunctioned and is not able to power up the fuser’s heater.

2        Failed heater in the fuser.  The fuser itself is at fault in this situation, replace as necessary.

3        Defective DC controller board.  The board is not sending the signal to the power supply to turn on the fuser's heater.