IBM 5155 Manual To Operations page 179

6
Does the black area appear across the top and
bottom of the screen?
•
()
8
YES - Go to the next step.
NO - Have the display serviced.
7
Are the black areas at the top and bottom of the
screen approximately equal in size?
•
()
8
YES - Go to the next step.
NO - Have the display serviced.
January 1984 Test 9000-3