Power Mac G4

Power Mac G4

A graphite Power Mac G4 (400 MHz). Photo: Marco Stadelmaier, Wikimedia Commons, CC BY-SA 3.0
Specifications
Manufacturer	Apple Computer, Inc.
Type	Tower personal computer
Released	1999 (PCI Graphics and AGP Graphics; Apple's specification pages give 15 September 1999)
CPU	PowerPC G4 at 350 MHz to 1.42 GHz, single or dual by model
Memory	PC100 or PC133 SDRAM (1999–2002); DDR SDRAM on the Mirrored Drive Doors models
Storage	Ultra ATA hard drive; up to three internal drives (four on Mirrored Drive Doors models)
Display	—
Sound	—
Graphics	Video card in a dedicated slot: PCI on the PCI Graphics model, AGP 2X or 4X on later models
Ports / interface	USB, FireWire, 10/100 or 10/100/1000 Ethernet, VGA, ADC or DVI by model
Power	115 V or 230 V AC set by a switch on the power supply (to the QuickSilver 2002)
Dimensions	17.0 × 8.9 × 18.4 in (43.2 × 22.6 × 46.7 cm)
Weight	30–42 lb by model
OS / Firmware	—

The Power Mac G4 is Apple's family of tower Macintoshes built around the PowerPC G4 processor, sold from 1999. Apple's service manual describes the Power Mac G4 as "the first Power Mac computer based on the PowerPC G4 processor" and lists six tower models up to early 2002: PCI Graphics, AGP Graphics, Gigabit Ethernet, Digital Audio, QuickSilver and QuickSilver 2002. The Mirrored Drive Doors models followed in 2002 and 2003 with their own manual. The Power Mac G4 Cube used the same name and processor in a separate small enclosure, and the Macintosh Server G4 was the tower sold with server software.

EveryMac describes the tower case as the design introduced with the blue and white Power Macintosh G3. To open it, lift the latch on the right side panel and lower the panel until it lies flat, exposing the logic board (p. 28).

Models

Power Mac G4 tower models

Model	Introduced	Processors	System bus	Memory	Slots
PCI Graphics	15 September 1999 (Apple)	350, 400 MHz	100 MHz	PC100, 4 DIMM slots	4 PCI, one holding the video card
AGP Graphics	15 September 1999 (Apple); announced 31 August 1999 (Low End Mac)	350–500 MHz	100 MHz	PC100, 4 DIMM slots	3 PCI and AGP 2X
Gigabit Ethernet	19 July 2000 (Low End Mac)	400 MHz; dual 450 or 500 MHz	100 MHz	PC100, 4 DIMM slots	3 PCI and AGP 2X
Digital Audio	9 January 2001 (Low End Mac)	466, 533, 733 MHz; dual 533 MHz	133 MHz	PC133, 3 DIMM slots	4 PCI and AGP 4X
QuickSilver	18 July 2001 (Low End Mac)	733, 867 MHz; dual 800 MHz	133 MHz	PC133, 3 DIMM slots	4 PCI and AGP 4X
QuickSilver 2002	28 January 2002 (Low End Mac)	800, 933 MHz; dual 1 GHz	133 MHz	PC133, 3 DIMM slots	4 PCI and AGP 4X
Mirrored Drive Doors	13 August 2002 (Low End Mac)	Dual 867 MHz, 1 GHz or 1.25 GHz	133 or 167 MHz	DDR SDRAM, 4 DIMM slots	4 PCI and AGP 4X
Mirrored Drive Doors (FW800) and 2003	2003 (Apple)	1 GHz to dual 1.42 GHz; single 1.25 GHz (2003)	133 or 167 MHz	DDR SDRAM, 4 DIMM slots	4 PCI and AGP 4X

Sources: Apple's specification pages, the model pages and Low End Mac.

Telling the models apart

Apple's service manual identifies the 1999–2002 towers like this (pp. 4–5, 23–25):

• QuickSilver and QuickSilver 2002: silver case with a recessed speaker in the front panel.
• PCI Graphics: graphite case; the sound ports run horizontally in the lower half of the rear I/O panel.
• AGP Graphics and Gigabit Ethernet: graphite case; the sound ports run vertically. AGP Graphics logic boards have an internal FireWire connector at J9 and Gigabit Ethernet boards do not.
• Digital Audio: graphite case; the sound ports sit in the upper half of the I/O panel, and there are four PCI slots plus the AGP slot instead of three.

The Mirrored Drive Doors model has a speaker in the top of the case and mirrored optical drive bezels.

PCI Graphics

The first G4 tower, which Low End Mac calls the "Yikes!" model, used a modified blue and white G3 logic board with PCI video. It differs from every later G4 in ways that matter for repair (pp. 207, 212–219, 239):

• It has a Cuda microcontroller with its own reset button beside the battery, not a PMU. Apple's board reset for this model is to unplug it, press the front power button, take out the battery for at least ten minutes, and refit it the right way round.
• Its processor module needs a jumper block at J25 of the right colour for the processor fitted, with all its inner metal clips, the right way round; without it the machine does not boot. Apple supplies the block with a replacement logic board and warranty sticker (076-0760 for 350 MHz, 076-0758 for 400 MHz).
• Seven diagnostic LEDs on the board (DS1, DS4–DS9) show ATA activity, USB power, Ultra ATA activity, power and processor bus requests.
• Four or five beeps at start-up mean a bad boot ROM checksum.

Apple's parts for it are logic board 661-2253 and power supply 661-2256, the same supply number as the AGP Graphics model (pp. 276, 291).

Mirrored Drive Doors

The last G4 towers take DDR memory: PC2100 in 133 MHz machines and PC2700 in 167 MHz machines. PC2100 memory in a 167 MHz machine stops it booting with a single tone and a flashing front light. They hold four hard drives in two carriers, with the 100 MHz ATA cable in the rear carrier and the 66 MHz cable in the front, which Apple says must not be swapped. Apple also notes that several bus-powered FireWire devices with an Apple ADC 17-inch CRT display can exceed the supply's capacity and shut the system down (p. 112). The supply connector and test points are tabulated on Power Mac G4 (Mirrored Drive Doors) Service Source.

Common service points

• Every tower model to the QuickSilver 2002 has a supply voltage switch that must be set for the local mains (115 V in North America) whenever a supply is replaced, and Apple's first check for a dead machine includes it (pp. 143, 149, 237).
• The clock battery is a 3.6 V lithium cell (part 922-4028 on every tower model in Apple's exploded views). The PMU-based boards want it between 3.3 and 3.7 V before a PMU reset (pp. 210, 276–291).
• The logic board needs a standby "trickle" supply to start: +5 V on the PCI and AGP Graphics, +28 V on the Gigabit Ethernet and Digital Audio, +25 V on the QuickSilvers (p. 220).
• All the 1999–2002 towers share the 922-3295 case fan (pp. 276–291).
• Low End Mac reports that G4 towers before the QuickSilver 2002 do not support ATA drives over 128 GB on the internal bus without third-party help, and that some 2001 QuickSilvers with a later logic board do.

The step-by-step procedures are on the shared guides:

• Power Mac G4 General Maintenance: opening the case, battery, PMU reset, memory, processor and power supply removal
• Power Mac G4 Troubleshooting: power-on self test, power supply verification, Apple's symptom charts and community power supply repair notes

Model pages

• Power Mac G4 (AGP Graphics)
• Power Mac G4 (Gigabit Ethernet)
• Power Mac G4 (Digital Audio)
• Power Mac G4 (Quicksilver)
• Power Mac G4 Cube
• Macintosh Server G4

Documentation

• Power Mac G4/Macintosh Server G4 Service Source: PCI Graphics to QuickSilver 2002 and the Macintosh Server G4
• Power Mac G4 (Mirrored Drive Doors) Service Source
• Power Mac G4 Cube Service Source

Gallery

• 
  Apple's views of the AGP Graphics and Gigabit Ethernet models
• 
  Power Mac G4 (QuickSilver). Photo: baku13, CC BY-SA 3.0
• 
  Graphite G4 with the side door open. Photo: Marco Stadelmaier, CC BY-SA 3.0
• 
  Power Mac G4 Cube. Photo: Binarysequence, CC BY-SA 4.0