Apple Desktop Computer manual Removing the bottom cover, Unfastening the Cables

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C H A P T E R 4

RAM Expansion

Figure 4-1Bottom view showing bottom cover handle

Handle

Retaining screw

Removing the bottom cover

The bottom cover is held in place by a retaining screw located on the bottom cover and accessible through the opening in the handle. After removing the screw, the user can remove the cover by pulling up and out on the handle.

Unfastening the Cables

Several signal cables are connected to the back of the logic board assembly, as shown in Figure 4-2. Those must be disconnected and freed from their clamps. Once the cables and clamps are disconnected, the user should position the cables to either side of the logic board assembly, as shown in Figure 4-3.

The Expansion Slots

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Contents Apple iMac Computer Page Contents RAM Expansion Devices and PortsRtas SoftwareRtas NV-RAM Appendix Abbreviations IndexFigures and Tables Page About This Developer Note Contents of This NoteATA Devices PowerPC G3 MicroprocessorSupplemental Reference Documents Mac OSOpen Firmware USB DevicesE F a C E Introduction Features Shows a front view of the computer Case and External FeaturesFront view 2Side view showing I/O bay System Software Compatibility IssuesVideo RAM Expansion Modules Main RAM Expansion ModulesUSB Ports and Devices Page Architecture Architecture G3 Microprocessor Processor moduleBackside Cache Memory Controller and PCI Bridge Main Logic BoardController IC Video Display Subsystem USB ControllerBuilt-in Modem Infrared Link Module Devices and Ports USB Ports USB ConnectorsGND Transfer Types SupportedADB Compatibility USB Compatibility IssuesUSB Controller Serial Port CompatibilityMacintosh-To-Macintosh Connections USB Storage DevicesKeyboard Layout KeyboardKeyboard and USB MouseVideo Display Hard Disk DriveSound System Infrared Communication LinkExternal Sound Input Sound InputsSound Outputs Built-in MicrophoneExternal Sound Output Sound SpeciﬁcationsHeadphone Jacks Total harmonic distortion Internal Modem Ethernet PortPage RAM Expansion Expansion Slots Removing the Logic Board AssemblyPlacing the Computer Face Down Unfastening the Cables Removing the bottom coverRAM Expansion Removing the Retaining Screws 3Logic board assembly handle and retaining screwsRemoving the EMI Shield Removing the Logic Board AssemblyLocations of the Expansion Slots 6Locations of the RAM expansion slots Main RAM ExpansionElectrical Design of RAM SO-DIMMs Mechanical Design of RAM SO-DIMMsSdram Devices Conﬁguration of RAM SO-DIMMs Address Multiplexing RAM SO-DIMM Electrical LimitsVideo RAM Expansion Page Software Why Make This Change? What Has Changed Features of the New Approach Data Structures and Files PerformanceRAM Footprint User ExperienceBoot ROM Contents Rtas Mac OS ndrv DriversToolbox Image File Contents Trampoline Code NewWorld Boot ProcessToolBox ROM Image Interrupt Handling What Is DifferentRAM Footprint Outmoded ResourcesStartup Disk Control Panel NanoKernelInterrupt Layout Open Firmware and the Device TreeMachine Identiﬁcation Software Abbreviations Chrp NMI Page Index Nvram X, Y, Z Allen Watson