MP 2852 buzzing/grinding noise

**rthonpm** · 07-12-2017

I've got a 2852 that makes a loud noise somewhere between buzzing and grinding every time the main motor runs. Here's the breakdown:

The developer gears in the PCU were packed with the stuff and shredded to the point where they wouldn't turn at all. My first thought was that this took the motor out with it, so after installing a new PCU I swapped motors with a known good machine, and the motor from the noisy machine works perfectly, while the good motor still generates a lot of noise. I've pulled out the drum drive pack and all of the gears look good: no cracks or chipped teeth. The shafts are a little dirty, but nothing that looks like it would cause issues.

I'm hoping that just ordering a new drum drive section will fix the issue, especially since trying to run a test print with the machine in its current condition just gives me a very faint image, as if there's no toner mixing with the developer.
Before I start going down the rabbit hole of drive related parts, I figured I'd see if anyone else has had a similar issue, or if I'm even on the right path.

**slimslob** · 07-12-2017

Look closely at the large nylon gears that the motor shaft contacts for slightly worn spots caused by the development unit binding and preventing the gear from turning but the motor still spins against it. I have had to replace a couple of the gear boxes.

**StephenB** · 07-12-2017

You may have a couple "things" going on. Pull the fuser, and inspect the drive assembly (inside machine ) which passes drive from the main motor.
I had some low volume machines strip these out.

**COPIERMAN** · 07-12-2017

go into service mode and turn main motor on in 5-804 output check. then open right side door push on interlock switch and listen for noise. If no noise then fuser area. can push metal plate on fuser to in gage if noise start then in that area . If no noise from fuser then pull pcu out close door and run it again if nosie gone then pcu area.