HP Color LaserJet 3800 Black print problem

[ultimateprintsolutions]

Printer came in with broken right lock lever, unable to test before replacement. I replaced the right lock lever and now has issue with the black print. When I print the supply status page it tries to print black at the top of the page (but doesn't) and does towards the bottom. I have R/R the gear pack several times and check the cams to make sure they are in the proper position. All toner motors are turning. I have tried a second transfer belt, known good black toner. I seem to think I have seen this problem before but my memory is failing me. See attached sample.

[ultimateprintsolutions]

Update, replaced the MDA (main drive assy) on the right side and it solved the problem.

[theengel]

This is a common problem when the gears aren't lined up properly.

Most of the guides out there tell you how to line everything up, but a lot of the guides miss the solenoid activated gears.

I'm going to take some pictures and post them later, because I can't remember what they're actually called and what they drive.

[Lance15]

I remember trying to realign the gears in the developing seperation-drive assembly once because of sticky solenoids. Figured easy peesey. Must have been missing something because after re-padding those solenoids, I couldn't get the gears realigned properly. Ended up just replacing it.

[theengel]

You have to activate the solenoid by hand, and then turn the gears by hand until the solenoid catches again. Then make sure it's facing the right way. If it's facing the wrong way, do it one more time. You have to do this once for the black, and once for the colors. The way I'm saying it doesn't make much sense without pictures. I'm hoping sometime in the next couple of weeks I get one--that way I can take some pics or video.

[faxman28]

attached is the hp doc for aligning/replacing MDA.

[theengel]

Again--this doesn't describe how to make sure the gears around the solenoids are in the right place. Sometimes, especially the 1st few times people do it, the solenoids get touched or screwed with. If they've been activated, even though all the gears look like they're in the right place, the colors will be messed up. You have to turn those top gears until the solenoids catch again.