Apple 1705 Computer Monitor User Manual

Troubleshooting Symptom Charts/Video - 8
Screen flickers 1 Check the monitor cable connections. The thumbscrews
must be tightened securely. If a video card is used, the
monitor cable must be secured to the card.
2 Check for external interference by moving the monitor to
another location.
3 If using more than one monitor with a computer, move the
monitors so they are least 18 inches apart.
4 If a video card is used, check the refresh rate. Refresh
rates below 60 Hz may cause flicker. See the video card
manual to raise the refresh rate above 60 Hz.
5 Doublecheck items 1 through 4.
6 Replace the video and main deflection boards. See “Main
Deflection, CRT/Video Boards and Rear Fence” in Take
Apart. Adjust cutoff and white balance. See “Cutoff and
White Balance” in Adjustments.