A werid problem happend with me on this machine ,the machine was at costumer and it was workedfine,suddenly when its was copying the machine screen turend black and only the green led light,i turned it off then off same black screen, i have changed Dc pcb ,main control, power supply and still until i changed the drum the machine worked,when it come back on it ready condition started to jam on every paper when insided the fuser then i changed the motor 2 and still also changed the main unit and still ,it made me crazy ,the. I dessamble the dc pcb and turned it back it works without any jam around 200 k and the. The machine turned black screen and stopped ,i removed the drum and i found that the heater drum is burned changed ot and it works ,the it stopped agaon .really werid lroblem ,by the way there a note when i turned on the machine it showed me a jam inside the machine and there was nothing i just opened the door and close it it works this happend when turned on the machine .