Hello, I had the same thing on the Phaser 850, I followed the step posted on this forum, and with a little bit of time I fix my problem. Oh I also to went to home depot for the bulbs.
I would first check the sensors, use either q-tip or some computer dust off air(can air) not sure of the name. Something if the sensor get ink or dust on it the printer thinks it not ready. Also make sure the printer has 4 inch on each side to function correctly.
Also it you fix the unit your self, try to have a clutch pully tool handy. Something the clutch/moter/gear is on the shaft real tight.
There is a guy on ebay the sell the drum heater repair kits plus the video instructions to replace them. I did not go for them 40 dollars plus 9 dollars shipping.
The bulbs at home depot are the 120v / 150 watt halogens. the cost is about 9 to 13 dollars. So if you see them on sale pick to up.
If I was to redo the drum heater repair again, I would and it would take about 45 mins only. I now know to do. It hard at all.