Apple Desktop Computer manual Expansion Slots, Removing the Logic Board Assembly

Page 42

C H A P T E R 4

RAM Expansion

This chapter tells how to gain access to the expansion slots in the iMac computer and describes the two types of RAM expansion: main RAM expansion and video RAM expansion.

The Expansion Slots

To get access to the expansion slots, the user must open up the bottom of the computer and remove the main logic board and processor module assembly.

IMPORTANT

The user should be reminded to observe the usual precautions to avoid damage to the electronic components due to static electricity.

Removing the Logic Board Assembly

The steps in removing the logic board assembly are:

1.Place the computer face down on a soft cloth.

2.Remove the retaining screw and the bottom cover.

3.Unfasten the cables attached to the logic board assembly.

4.Remove the retaining screws.

5.Pull out the logic board assembly.

The following sections describe the steps.

Placing the Computer Face Down

To remove the logic board from the computer, the user must first gain access to the bottom of the computer by placing the computer face down on a soft cloth, as shown in Figure 4-1.

42The Expansion Slots

Image 42
Contents Apple iMac Computer Page Contents Devices and Ports RAM ExpansionSoftware RtasAppendix Abbreviations Index Rtas NV-RAMFigures and Tables Page Contents of This Note About This Developer NoteMac OS PowerPC G3 MicroprocessorSupplemental Reference Documents ATA DevicesUSB Devices Open FirmwareE F a C E Introduction Features Case and External Features Shows a front view of the computerFront view 2Side view showing I/O bay Compatibility Issues System SoftwareMain RAM Expansion Modules Video RAM Expansion ModulesUSB Ports and Devices Page Architecture Architecture Processor module G3 MicroprocessorBackside Cache Main Logic Board Memory Controller and PCI BridgeController IC USB Controller Video Display SubsystemBuilt-in Modem Infrared Link Module Devices and Ports USB Connectors USB PortsTransfer Types Supported GNDUSB Compatibility Issues ADB CompatibilityUSB Storage Devices Serial Port CompatibilityMacintosh-To-Macintosh Connections USB ControllerKeyboard Keyboard LayoutMouse Keyboard and USBHard Disk Drive Video DisplayInfrared Communication Link Sound SystemBuilt-in Microphone Sound InputsSound Outputs External Sound InputSound Specifications External Sound OutputHeadphone Jacks Total harmonic distortion Ethernet Port Internal ModemPage RAM Expansion Removing the Logic Board Assembly Expansion SlotsPlacing the Computer Face Down Removing the bottom cover Unfastening the CablesRAM Expansion 3Logic board assembly handle and retaining screws Removing the Retaining ScrewsRemoving the Logic Board Assembly Removing the EMI ShieldLocations of the Expansion Slots Main RAM Expansion 6Locations of the RAM expansion slotsMechanical Design of RAM SO-DIMMs Electrical Design of RAM SO-DIMMsSdram Devices Configuration of RAM SO-DIMMs RAM SO-DIMM Electrical Limits Address MultiplexingVideo RAM Expansion Page Software Why Make This Change? What Has Changed Features of the New Approach User Experience PerformanceRAM Footprint Data Structures and FilesBoot ROM Contents Mac OS ndrv Drivers RtasToolbox Image File Contents NewWorld Boot Process Trampoline CodeToolBox ROM Image What Is Different Interrupt HandlingOutmoded Resources RAM FootprintNanoKernel Startup Disk Control PanelOpen Firmware and the Device Tree Interrupt LayoutMachine Identification Software Abbreviations Chrp NMI Page Index Nvram X, Y, Z Allen Watson