IBM Personal Computer XT Manual To Operations page 187

17
Is your screen blank?
NO - Go to the next step.
YES -
Have the unit to which the display was
attached serviced.
18
Is the screen presentation steady?
YES -
Go to Step 21.
NO - Go th the next step.
19
Turn the Vertical Hold control clockwise as far
as it will go, then turn it counterclockwise until
the presentation is steady.
o
Vertical Hold
Control
April 1984 Test 9000-7