Symptom
A display may exhibit symptoms such as no video, shaky or wavy images, incorrect color, specific color background, or Energy Saver control panel issues.
Products affected
Solution
- No video may be caused by a loose video card, loose video cable, bad RAM, corrupt Parameter RAM, Energy Saver setting, dead backup battery on the computer logic board, or display hardware issue.
- Check the video cable connections - Shut the system down and remove then reconnect all the display cables to verify they are tight. Check the cable for stress, crimping, or bending. If the cable was compressed, crimped, bent against a table, wall, or chair leg it may need to be replaced. Some video cables are integrated into the display and require a local Apple-authorized service provider to replace them. In some cases, the video cable cannot be replaced.
- Test the display on another computer - If the issue does not occur on the other computer the issue is with the first computer, computer's video card, or software.
- Radio interference can be difficult to locate. The best method is to test the display at a different building which uses a different power source. If the display is at a school or a building with a common power source, try another site. Shaking, waviness, or jittering can be caused by another nearby electrical device including a display, fan, transformer, or motor. Interference may be identified by rotating the display on its side or turning it to face a different direction. If the interference pattern changes or goes away, it may be an environmental interference issue.
- Test the display with the power cord plugged directly into the wall outlet and into the computer's power outlet if the computer has a power out port. If the display operates normally when the power cord is plugged into the wall outlet but fails when it is plugged into the computer outlet, the computer power supply is suspect and should be checked by a local Apple-authorized service provider.
- If the display needs to be repaired, contact an Apple-authorized service provider or Apple support to arrange service.