Specifications

Troubleshooting Symptom Charts/Video - 6
Video
Screen is dark, audio
and at least one drive
operate, fan is
running, and LED is
lit
1 Adjust brightness on monitor.
2 Clear parameter RAM. Hold down <Command> <Option>
<P><R> during startup but before Welcome to Mac appears.
3 Check cables.
4 Replace monitor. Refer to appropriate monitor manual to
troubleshoot defective monitor.
5 Replace video card.
6 Replace VRAM SIMMs.
7 Replace logic board. Retain customer’s SIMMs.
Screen is dark, audio
and drive do not
operate, fan is
running, and LED is
lit
1 Remove peripherals.
2 Remove NuBus cards.
3 Replace DRAM SIMMs.
4 Replace VRAM SIMMs.
5 Replace power supply.
6 Replace logic board.