IBM Personal Computer XT Manual To Operations page 184

8
Turn the Vertical Size control clockwise until the
black areas just disappear.
If
one of the black
areas disappears before the other, continue to
turn the control until the second black area is
gone.
Vertical Size
Control
9
Is the entire screen white?
bJ
()
•
0
•
YES -
Go to Step 14.
NO -
Go to the next step.
9000-4 Test
April 1984