HP HP 8753E, Service Manual, Page: 383 / 612

of Green (each band increasing in intensity) Black four bands of Blue
(each band increasing in intensity) Black If any one of the four bits for
each color is missing the display will not look as described.
75
10. Displays a character set for showing the user
the different types and sizes of characters available. Three sets
of characters are drawn in each of the three character sizes. 125
characters of each size are displayed. Characters 0 and 3 cannot be
drawn and several others are really control characters (such as carriage
return and line feed).
76
Pat 11.
Displays a bandwidth pattern for verifying the bandwidth
of the EXTERNAL display. It consists of multiple alternating white and
black vertical stripes. Each stripe should be clearly visible. A limited
bandwidth would smear these lines together. This is used to test the
quality of the external monitor.
77
12. Displays a repeating gray scale for troubleshooting, using
an oscilloscope. It is similar to the 16 step gray scale but is repeated 32
times across the screen. Each of the 3 outputs of the video palette will
then show 32 ramps (instead of one staircase) between each horizontal
sync pulse. This pattern is used to troubleshoot the pixel processing
circuit of the GSP board.
78
13. Displays a convergence pattern for measuring the
accuracy of the color convergence of the external monitor.
79-80
Pat 14-15.
Displays crosshatch and inverse crosshatch patterns
for testing color convergence, alignment. This is useful
when aligning the LCD display in the bezel.
Service Key Menus and Error Messages 1