HP Designjet 2800/3800cp Service Manual - Page 158

Only replace one component at a time and check if the problem has gone before replacing another component. Using this procedure you will be able to determine exactly which component failed. Test Pattern 5: Color Variation Test This test produces four boxes; black, blue, cyan and yellow. In each box there are three horizontal bands, the two outer bands are 100% shade, the inner band is shaded from 100% scaling to 75%. The purpose of this test is to determine at what percent the middle shading becomes visible from the two outer bands. The best way to do this is to cover the box with a piece of paper and slide the paper horizontally across the box. Stop as soon as you see a different shade in the middle box. You can then determine the percentage scaling from the figure at the top of the box. Example E (Correct) 6-16 Example F (Incorrect) HP DesignJet CP Series Printers Image Quality