HP M609 developer drive

[mascan42]

I have an M600 that lost developer drive. The drive pin on the gear was stuck in the retracted position & wouldn't move (even when removed from the machine). I replaced the gear and the drive unit, and now the pin moves freely back & forth, but it has no spring tension behind it so once it's pushed inward, it stays there unless I reach in & pull it out by hand. Any idea what might have gone wrong?

Also, I'm a little unclear on how the developing drive works. Does the solenoid activate a cam that pushes on the pin?

[Lance15]

Re: HP M609 developer drive

A printer that new should still be under warranty.

Series go:
M601-M603
M604-M606
M607-M609

There is a Developer alienation solenoid (SL2) that needs to be removed to remove the drive assembly.

Without seeing the guts of the developing drive assembly, you may have to figure out how it works on your own.

If it's anything similar to how the 42xx pickup assembly works, there is a gear (on the inside of the assembly) that has an odd shaped slide with a stop (for the solenoid "tip") to stop the gear from turning. This is how it tells the printer to start the next phase.