Sharp MX- 3100 prints and copies only Yellow

[John1619]

My MX-3100 prints and copies only yellow. I have checked the drums, developer units, they seem to be rotating and working. I replaced the laser unit and HVT. Still have the same problem. I have been through the service manual and cannot find anything in common with (CMK) that would cause this.The laser shutters work in unison, yellow is the last one. ANY ideas?? Your help is greatly appreciated.

[EasyRider]

Re: Sharp MX- 3100 prints and copies only Yellow

Check that LSU solenoid. Could be opening enough for the yellow, but not for the rest.
I've seen that solenoid covered in yellow toner/dv, causing this problem. Or weak/broken.

Good luck.

[spanky]

Re: Sharp MX- 3100 prints and copies only Yellow

Run shy shots for each color in the single color mode.

Stop the machine during the cycle to see if there is toner on the drum.

This will tell you if it could be the transfer belt.

If toner is not on the drum I would remove the LSU shutters and try again.

[Prints Charming]

Re: Sharp MX- 3100 prints and copies only Yellow

I have to agree with the above guys. Sounds alot like the shutters are not opening fully. As yellow is closest to the solenoid lever, it will open with the greatest force.
Take all drums & devs out. Run the Solenoid Shutter Test in sim 6-01. Look for 'LSUSS'. While the front door is open, block the door sensor and keep pressing execute on the screen for LSUSS. This will make the shutters open & close each time.
Look for the shutters not fully opening (they must pass complete vertical, to the left), shutters slowly closing by themselves, and all shutters opening/closing at the exact same time. Any of these not working correctly usually indicates the shutter solenoid is failing (usually from toner/dev falling down inside it), or the small spring has come off.
Take the left side cover off and take the LSU out. Place your magentized screwdriver next to the solenoid. If you get dev on the screwdriver, its a guarantee you have dev inside the solenoid, which is blocking the performance of it. You'll see the shutters will not work as good if the solenoid is contaminated.

It'd be rare for this to be a Main Drive Unit problem, as it's an all-in-one part. Other colors would be affected as well. Check the harness from the LSU to the motherboard next to the MFP board. Ensure it is plugged in correctly.

[ZOOTECH]

Re: Sharp MX- 3100 prints and copies only Yellow

Remove all the shutters, and run a test; if all colors are shown, that is where the problem is as the above posts indicate.

[Prints Charming]

Re: Sharp MX- 3100 prints and copies only Yellow

Remove all the shutters, and run a test; if all colors are shown, that is where the problem is as the above posts indicate.

Yes, Paul is right, however the shutter units are also the rails for the drum and dev units, so you won't be able to simply remove everything. You will need to either remove the moving shutter itself or tape them completely open.
Its a good test.