Specifications

Troubleshooting Symptom Charts/Video (Continued) - 7
Video
(Continued)
Partial or whole
screen is bright and
audio is present, but
no video information
is visible
1 Check cables
2 Clear parameter RAM. Hold down <Command> <Option>
<P><R> during startup but before Welcome to Macintosh
appears.
3 Replace monitor. Refer to appropriate monitor manual to
troubleshoot defective monitor.
4 Replace video cable.
5 Replace VRAM SIMMs.
6 Replace logic board. Retain customer’s SIMMs.
Screen is completely
dark, fan is not
running, and LED is
not lit
1 Verify that external power cables are properly connected.
2 Remove peripherals.
3 Remove NuBus cards.
4 Replace power supply.
5 Replace logic board. Retain customer’s SIMMs.