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K
Service Source
Power Macintosh G3
Desktop
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K Service Source Hot Issues Power Macintosh G3 Desktop
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Hot Issues Introduction - 1 Introduction This chapter is designed to highlight unique or high- priority product issues that you should be aware of before servicing the Power Macintosh G3 Desktop computer. This chapter alerts you to important issues and provides links to other areas in the manual where more complete information can be found. This chapter is not intended to replace other parts of this manual; it merely provides a pointer to pertinent information in those chapters. To f
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Hot Issues Shared Logic Board - 2 Shared Logic Board The Power Macintosh G3 Desktop and Minitower computers use the same logic board, but there are jumper settings that differ between them (see “Jumper Location J28” and “Jumper Location J16” in the Troubleshooting chapter). Processor Module Vs. Card Whereas previous Power Macintosh computers featured a user-installable processor card, this logic board uses a processor module that must not be removed by the customer (see “Processor M
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Hot Issues Power Supply Jumper - 3 Power Supply Jumper The Power Macintosh G3 Desktop logic board has a power supply jumper, which is installed at J28. The setting of this jumper differs between the Power Mac G3 Desktop and Minitower. Failure to install this jumper in the correct position may result in a computer that won’t boot up. (See “Jumper Location J28” in the Troubleshooting chapter.) Processor Module Jumper The Power Macintosh G3 Desktop logic board has a processor module ju
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Hot Issues Warranty Sticker - 4 Warranty Sticker There is a warranty sticker that covers the processor module jumper. The customer’s warranty is void if this sticker is tampered with. Service Providers must replace this sticker if they have removed it during servicing to protect the customer’s warranty. (See “Processor Module” in the Take-Apart chapter.) Power Supply Voltage Setting There is a switch on the back of the power supply that controls the voltage setting. The voltage sw
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Hot Issues Voltage Regulator - 5 Voltage Regulator There is a removable voltage regulator on the logic board, which comes with the logic board and can also be ordered as a separate module. (See “Voltage Regulator” in the Troubleshooting chapter.) I/O Card Some I/O functions on the logic board are handled through a removable I/O card that must be installed for the computer to operate properly. (See “I/O Cards” in the Troubleshooting chapter.)
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Hot Issues ROM DIMM - 6 ROM DIMM The Power Macintosh G3 Desktop logic board uses a ROM DIMM as opposed to soldered ROM. You should not remove the ROM DIMM from the logic board. (See “Logic Board” in the Take-Apart chapter for instructions on how to prepare the logic board for return to Apple Computer.) SDRAM DIMMs The Power Macintosh G3 Desktop uses SDRAM DIMMs. DIMMs from older Macintosh computers, although they will fit, are not compatible and should never be used in the Power Ma
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Hot Issues SGRAM Video Memory - 7 SGRAM Video Memory Power Macintosh G3 computers use SGRAM video memory. Use only SGRAM SO-DIMMs in these machines. Never install the 256K or 512K video memory DIMMs used in older Macintosh computers. (See “SGRAM Video Memory” in the Basics chapter.) EIDE Bus Issue If you have only one device connected to the EIDE bus, the device must be plugged into the first EIDE connector on the logic board (the one closer to the rear panel), which is marked J9.
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Hot Issues Master/Slave Support - 8 Master/Slave Support Some Power Macintosh G3 Desktop computers support adding two ATA/IDE devices to the same ATA/IDE channel, or what is commonly known as master and slave. This configuration provides user with the ability to add additional hard drives or removal media devices to their system. Because the cabling is different, you cannot replace ATA drives with SCSI drives and vice versa. (See “Support for Master and Slave” in the Basics chapter
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Hot Issues DVD-ROM Disk Damage - 9 the Take-Apart chapter.) DVD-ROM Disk Damage The Power Macintosh G3 Desktop offers DVD-ROM drives as a build-to-order option. It is important to note that DVD disks are much more prone to damage than CD-ROM disks. Any type of scratch or other abuse may result in a disk that is unreadable. (See “DVD-ROM Drive Technology” in the Basics chapter.) CD-ROM Ejection Problem If you have a CD-ROM drive in a Power Mac G3 Desktop that fails to eject CDs p
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Hot Issues HFS+ Formatted Drives - 10 HFS+ Formatted Drives Hard drives that ship with the Version 2 Power Macintosh G3 logic board (part number 661-2063) use a file format called Mac OS Extended format, also referred to as HFS+. Norton Utilities version 3.5 is not compatible with Mac OS and version 3.5.1 and earlier can result in hard drive corruption and loss of all data on the hard drive. If you experience problems with a hard drive in one of these systems, Apple Computer recommen
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Hot Issues Power-On Issue - 11 Power-On Issue If you experience a power-on issue with the Power Macintosh G3 Desktop where the power supply fan is spinning, but there is no boot tone, no hard drive noise, no power LED, and no video, you may have an improperly installed or faulty voltage regulator. You should always reseat and/or replace the voltage regulator before replacing the logic board. (See “System” symptom/cures in the Troubleshooting chapter.)
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K Service Source Basics Power Macintosh G3 Desktop
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Basics Overview - 1 Overview The Power Macintosh G3 desktop chassis design allows you to access the logic board and its components, including the removable processor, without having to remove the power supply or any drives. This flexible design makes this computer easy to service and upgrade. The Power Macintosh G3 desktop has a unique PERCH slot that accepts an I/O card that provides audio capabilities of the computer.
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Basics Overview - 2 Features of the Power Mac G3 Desktop include: • PowerPC G3 microprocessor running at 233 MHz, 266 MHz, or 300 MHz • RAM expandable to 384 MB in 3 DIMM card slots using 64-bit 168-pin JEDEC-standard 3.3 V unbuffered SDRAM DIMM cards (Note: to expand to the maximum capacity of 384 MB requires low-profile DIMMs with maximum height of 1.15”. Using higher-profile DIMMs with a height of 1.25”, the maximum SDRAM capacity is 192 MB.) • 512K backside L2 cache (233 or 266 M
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Basics Overview - 3 • Three expansion bays for adding internal 3.5-inch SCSI devices • Optional 100 MB SCSI Iomega or ATAPI Zip drive in one of the expansion bays • CD-ROM ATAPI drive at 24X speed (unless customer orders DVD-ROM drive) • 1.4 MB SuperDrive • One SCSI port • Two GeoPort serial ports • 10BASE-T Ethernet port • One ADB port • Three PCI expansion slots to accept • three 7-inch or 12-inch PCI cards, or • three 15 W cards, or • two 25 W cards • Voltage switch • Fan speed ther
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Basics Overview - 4 • 2 MB video RAM expandable to 4 MB or 6 MB with 3.3 V, 83 MHz or faster SGRAM on a 144-pin small outline dual inline memory module (SO-DIMM) Optional Build-to-Order Power Mac G3 Desktop Features: • ATAPI or SCSI Zip drive • Ultra Wide SCSI PCI card • 4 GB or 9 GB Ultra Wide 3.5” SCSI hard drive(s) (replaces 4 GB or 6 GB ATA hard drive(s)) • DVD-ROM Drive (in place of CD-ROM drive) • 10/100 BaseT ethernet card • FireWire DVC card
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Basics Data Buses - 5 Data Buses The data buses on the Power Macintosh G3 Desktop include: • Narrow SCSI-1: The SCSI-1 chain transfers data at up to 5 MB per second. The narrow SCSI-1 chain supports up to seven internal and external SCSI devices. The Narrow SCSI-1 bus is used to connect the ZIP drive (if present) and any SCSI-1 hard drives. • Ultra Wide SCSI-3 (provided on Ultra Wide SCSI card, which is optional): The Ultra Wide SCSI-3 chain can transfer data at up to 40 MB per second
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Basics Data Buses - 6 Note: Some Power Mac G3 system use a Master/Slave interface. See “Support for Master and Slave” later in this section for more information. The following table gives more information about the data buses in the Power Macintosh G3 Desktop computer.
