DI551 Light background

[Bill T.]

Customer calls in for "copies have light background. After cleaning up overtoning issue, determined it needed a developer change. 175K on Dev/PM. Performed ALL procedures in manual after Dev. change, also replaced blade. Ran a few copies it looked great customer was happy, I left. 200 copies later she calls back complaing about background again. Upon closer inspection when I stop copy half way I can see on the drum a very light toner covering the drum. I have tried to change Charge voltage, Grid voltage and Bias to no avail. What else could it be? Many Thanks, Bill T..

[fixthecopier]

I have had issues with copy quality on a couple of these, with symptoms like you describe, having good copies when yo leave and going downhill after a few hundred copies. I cleaned all contact points and got better results when I changed the drum with the developer.

[Downunder]

Have you checked to make sure discharge lamps coming on.


ATDC sensor settings should be set to about 4.8

[Lefty]

background

I've seen this problem many times its usually a bias problem. Pull out the dev unit and check the resistance between the bias pin and the mag roller if it is higher than 80 ohms replace the bearing on the rear side of the mag shaft. K. M. does have a mod for this problem.

[lvangsnes]

You may want to check your LD1 and LD2 bias adjustments. If they are out of range, you can get some overtoning. I have replaced many a developer unit for that model also for backgrounding. I have done the "mod" that KM suggests. They haven't worked. The d/u replacement costs some money, but saves time.

[mitchl]

Jeez not a Di-551/650 with CQ problems, that's sort of strange.............. NOT! If you do a search in this forum you will find a rather lengthy post by a gentleman from Wisconsin, this is sort of the gospel for getting these swines to settle down and not puke all over themselves. Follow the procedure to a T and you will find these machines run much cleaner with less CQ problems................ You want to also check and make sure the cleaning clutch hasn't seized up as this will cause gray background every time, guaranteed!