Light fall off Kaiser Vpm 7005 enlarger

[J. Borger]

I am using a Kaiser VPM 7005 enlarger. That is an enlarger with a Variable contrast head. I work in 6x6 B&W mainly.
I am fightin light fall off. I see (unacceptabel?) vignetting in all corners.
Even printing 6x6 negatives at 9 by 9 inch is a challenge, needing a lot of burning in of the corners ( about 3 x the total exposure time of the negative extra for the corners). I can not believe this is normal behaviour for this enlarger at this print sizes??
I checked the lamp (it is the correct hallogen lamp and it is fitted as it should), have the right lens (80mm) and lenspanel etc.

Any pointers or remedies?

Thanks in advance.

 

[J. Borger]

Kaiser customer service did a terrific job helping me trouble shoot the issue. It turned out the former owner did not fit the lensring correctly.
never questioned that because it was a professional wedding photographer who had used the enlarger like that.

Kaiser customer service was awesome, realy rare these days with companies.
And they knew i bought the enlarger 2nd hand.