Apple Macintosh Performa 577 - Manual (Page 19)

Troubleshooting Symptom Charts/Video - 2
Symptom Charts
Video
Screen is black, too
dark, or too bright;
audio and drive
operate
1 Adjust contrast button on front bezel.
2 Adjust brightness. Use Screen Control Panel.
3 Check yoke cable connection.
4 Perform video adjustments. Refer to “Video” in Adjustments
chapter.
5 Replace analog board.
6 Replace CRT.
Screen is bright and
audio is present, but
no video information
is visible
1 Perform video adjustments. Refer to “Video” in Adjustments
chapter.
2 Replace analog board.
3 Replace CRT.