Phaser 850 heating problem 1

[julbac]

Good morning,
firstly thanks to all of you that take the time to provide solutions, I've learnt a great deal about Xerox issues since joining recentlty.
My problem is with an 850 with error code 13.004.43:92648.
I now know that it could mean that the left side heater on the print head is at fault and may mean replacing the print head.
QUESTIONS:
1/Can any other causes produce the error code, ie.excess hardened ink around heater area or temperature sensor?
2/Can a faulty paper pre-heater produce that error?
I have read on this forum about 2 heater lamps that can be seen from the right of the printer, I have removed both left and right cover and observed the printer in operation in total darkness but can see no light!
3/Will an 840 print head work in an 850?
4/Drum-print head gap separation has been mentioned in a couple of posts, how is this gap adjusted and to what specs?
Thanks.

 

[jdwvw]

Do not adjust the head on an 850 on up. (only 840)

It is possible for a drum heater not working to cause this error but not very likely. The bulbs are cheap so I would try that first if you dont think they are working.

 

[julbac]

Thanks for your reply,
I learnt a quick way to check the 2 bulbs in the heater assembly on an 840 without having to remove the unit,pins 3 & 5 (from left)on the bottom row of the assembly socket, with plug removed, should read 20 Ohms if both bulbs are ok.
The socket is accessible with the right cover removed and is located below and to left of fan.

Am I right in assuming that the heater assembly is only powered up during the printing process, not during the printer initial printhead warm up?

 

[jdwvw]

They should be on (pulsing) during the warm up and some during printing.