HP4 57 Service

[Ralph]

I have an HP 4 with a 57 service error code. I have replaced the main motor and still get the error. Any suggestions on what else it could be?

[prntrfxr]

Remove the fuser.

Then, do the gears turn freely when you manually turn the motor?
If not, replace the gear drive assembly.
If they do check fuser gears, make sure they are not seized up and that they turn.
If that checks out good, then its probably a bad DC Controller.

This printer is a boat anchor, though. Unless customer wants to keep it, suggest upgrading to something else.

[redcow]

Check the toner cartridge. Binding gears will cause the problem.
You've already replaced the Main Motor, could be missing +24V on the DC Controller. Replace the DC Controller if the toner cartridge doesn't do it.

Boat Anchor? Maintained, it's a good reliable printer. A little old and slow...