Noritsu 3801G - Highlights Discolored

[ZTek]

Hello,
We are having some color issues in the highlights with our Noritsu 3801G. Shades of white to light gray come out greenish yellow and our highlights are a little overexposed.

We dumped chemical tanks, remixed fresh, and ran/plotted control strips. Our chemistry is in acceptable ranges(≤0.05), however the issue persists.
We print on Fuji CA Glossy/Luster and Fuji DPII Luster, the color shift is visible on all three papers but DPII looks considerably worse. I've reregistered our papers and ran almost every type of balance. Highlight balance I believed would have corrected it but it doesn't and the highlight balance strip looks overexposed and green as well.

I've attached some screenshots of the balance strip data and the highlight balance strip data. Also screenshots of a digital file vs a scan of a print to really show the issue.

Any advice would be greatly appreciated, thank you! 

Problem Images

[Dave S]

I can't see your images, I get a content not available in your region error.

How old is the calibration plate?
If it's the plastic type, they tend to yellow with age causing calibration problems.
The new calibration plates are ceramic so don't have this problem.

[ZTek]

Hi Dave, sorry about the images I'll upload directly.

As far as I know our calibration plate is the original one that came with our machine. That would make it about 11 years old. I can confirm it is a ceramic plate though.

[Dave S]

First try cleaning the calibration plate with some liquid soap and water.
See if it makes any difference.

To me it looks like the colorimeter is not reading properly.
Inside the colorimeter unit there is a solenoid that pushes the print up towards the colorimeter head, check this is working properly, if there is a gap between the head and the print it will not properly read, especially on the light steps.

[ZTek]

Cleaned the calibration plate but I don't see a change in the prints, still the same issue.

Is there a method to test if the solenoid is pushing the print all the way? I went into the "Output Check" maintenance and executed the "Pressure Change Solenoid" and can hear it click into place and when I hit cancel I hear it click back. So it 'works' but I'm unsure how to verify its making proper contact. Do you have any suggestions?

[Dave S]

If you take the covers off the colorimeter, then remove the colorimeter head, when you operate the solenoid in output check you should see a plate lift up, manually feed a print in and check it pushes the paper up enough to touch the bottom of the colorimeter mount.