Raster Drift - Control Data Corporation CDC CC63X Hardware Maintenance Manual

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RASTER DRIFT
The CC63X display terminal has a terminal installation parameter
that allows the installer or operator to move the raster left or
right and/or up or down. This allows for correction of raster
drift due to CRT aging. At the factory, the parameter values are
set at zero (no displacement) before the vertical and horizontal
centering alignments are made to the monitor board. As the CRT
ages, the customer or operator can use this parameter to center a
raster that has started to drift.
Before any monitor board adjustments are made in the field, the
parameter values or displacement values must be set at zero.
Proceed as follows to check the present parameter values and zero
if necessary.
1. Power on the terminal (procedure 1), if not already power
on.
2. Pullout the TEST switch.
3. Press RESET switch (initiate TESTl).
4.
When the MODE SELECTION MENU appears on the screen, push
the TEST switch in.
5. Press CTRL and SETUP keys. This will display terminal
installation parameters.
(See figure B-1.)
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62940034
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J.I----
UP /DOWN . DISPLACEMENT VALUE
------~t~--~----~---------LEFT/RIGHT
DISPLACEMENT VALUE
Figure B-1. Terminal Installation Parameters
B-1
B