Apple Macintosh Performa 577 - Manual (Page 126)

Adjustments Geometry - 5
Vertical Size
1 Using a hex-head plastic
adjustment tool, adjust
the vertical height (VH)
control until the raster
height is 7 inches
(± 1/8 inch) or 176
mm (± 2 mm).
2 Verify this height. If it
is off, repeat the
vertical size adjustment
and, if necessary, the
vertical center
adjustment.
All-White Screen