Macintosh SE: Video Display Linearity Adjustments



Using a Macintosh SE, I have drawn three circles of equal size on the same
horizontal axis. The circles are touching. When I measure the diameter of the
circles on the screen, I find that although the right-hand one is OK, the
left-hand one is 1/8 of an inch too narrow.

What's the official way of measuring screen linearity? What is the acceptable
tolerance? Does Apple set up the CRT magnets or are they set up by the CRT
supplier? How do I have them reset?

Acceptable tolerance for linearity is approximately 10 percent (horizontal and
vertical). That is, an object moved from one place to another will grow or
shrink by no more than 10 percent. The CRT magnets, installed by the supplier,
are extremely difficult to adjust and should not be moved, even by a service
representative. There is no way to adjust linearity of the Macintosh SE
display. Apple Manufacturing has developed test patterns to measure linearity.

If the user is dissatisfied with the appearance of the display, the analog
sweep PRINTED CIRCUIT BOARD should be replaced by an authorized service
provider.


Published Date: Feb 18, 2012