När du startar upp iMacen, snurrar då fläkten?
OK, har nu kollat upp lite grejer. Rev.B skiljer sig visst en hel del i "uppbyggnad" om man jämför med det som kom senare. Om fläkten ej snurrar och startknappen ej lyser (dator död) så är det inte alls säkert att det här rör sig om något fel i analog-kortet. Utan vad som kanske behöver göras är att resetta moderkortet:
Logic Board Battery
The battery on the logic board controls the stored system settings, such as date and time. It is important to note that the battery does not affect power at startup. The battery should be replaced if the system loses date and time settings.
The Cuda Chip
The Cuda is a microcontroller chip. Its function is to: • Turn system power on and off. • Manage system resets from various commands. • Maintain parameter RAM (PRAM). • Manage the real-time clock. Many system problems can be resolved by resetting the Cuda chip (see the Symptom/Cure tables for examples). Press the Cuda reset button on the logic board to reset the Cuda chip. (The Cuda reset button is located on the back edge of the logic board between the modem port and the processor module. Refer to the Logic Board Diagram in the Basics chapter for location information.) If you continue to experience system problems, refer to “Resetting the Logic Board” later in this chapter.
Resetting the Logic Board
Resetting the logic board can resolve many system problems (see the Symptom/Cure tables for examples). Whenever you have a unit that fails to power up, you should follow this procedure before replacing any modules. 1. Unplug the computer. 2. Disconnect the cable that runs from the power supply to the power filter board on the bottom side of the logic board/mass storage chassis. 3. Press the Power On button on the front of the unit. 4. Remove the logic board/mass storage chassis from the unit. 5. Remove the battery from the logic board. 6. Wait at least 10 minutes before replacing the battery. 7. Make sure the battery is installed in the correct +/- direction. 8. Reassemble the computer and test the unit. Note: This procedure resets the computer’s PRAM. Be sure to check the computer’s time/date and other system parameter settings afterwards.
