User Guide

Troubleshooting Symptom Charts/ Video Problems - 20
Distorted video.
Screen geometry is
out of adjustment or
screen is out focus.
1 Adjust the focus using the Display Adjustment Utility on the
MacTest Pro CD. (See “Focus” in the iMac Adjustments
chapter for instructions.)
2 Adjust the screen geometry using the Display Adjustment
Utility on the MacTest Pro CD. (See “Geometry” in the iMac
Adjustments chapter for instructions.)
3 Adjust the cutoff or white balance using the Display
Adjustment and Display Service Utilities on the MacTest Pro
CD. (See “Video” in the iMac Adjustments chapter.)
A a thin, white
horizontal line
scrolls from top to
bottom, or bottom to
top on the iMac
display.
1 Adjust the cutoff and white balance using the Display
Adjustment Utility on the MacTest Pro CD. (See “Video” in
the iMac Adjustments chapter for instructions.).
2 Replace the analog/video board. Refer to the Service Parts
Database for the correct part number, there are two versions
of the analog/video board.