HP 450c Service Manual - Page 87

3 If the problem continues perform the Accuracy Calibration (Details ' page 5Ć2) and print the PrintĆQuality Plot again to see if there has been any improvement. 4 If the error continues try the following: D Replace the Trailing Cable ' page 8Ć8. D Replace the Carriage Assembly ' page 8Ć37. D Replace the XĆaxis Assembly ' page 8Ć23. 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 two horizontal bands, the lower band is 100% shade, the upper band is shaded from 100% scaling to 60%. The purpose of this test is to determine at what percent the upper shading becomes visible from the lower band. 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 upper box. You can then determine the percentage scaling from the figure at the top or bottom of the box. Figure 7 (Correct) Print Quality Figure 8 (Incorrect) HP DesignJet 430, 450C and 455CA Printers 6-11