Introduction

The PowerMac G4 MDD (Mirrored Drive Doors) was apple's G4-Based Flagship from 2002-2004. All revisions of this computer can run leopard (With 512MB+) It has a mirrored finish on the drive covers, hence the term "Mirrored Drive Doors." This computer replaced the powermac G4 "Quicksilver" and was replaced by the PowerMac G5 In 2004. These computers came with CPU's with the following clock speeds; 867Mhz, 1Ghz, and 1.25Ghz in single and dual configurations, as well as a Dual 1.42Ghz Model. Later revisions of the 1.25Ghz and Dual 1.42Ghz Models supported AirPort Extreme instead of original Airport, and FireWire 800, These Computers were the first macs that could not boot into OS9.

This teardown is not a repair guide. To repair your Power Mac G4 MDD, use our service manual.

  1. The Power Mac G4 MDD: the last, and the fastest G4-based Mac.  This computer boasted up to a Dual 1.42GHz PowerPC G4 CPU (though I have a single 1.25GHz).
    • The Power Mac G4 MDD: the last, and the fastest G4-based Mac. This computer boasted up to a Dual 1.42GHz PowerPC G4 CPU (though I have a single 1.25GHz).

    • Six USB ports.

    • Four FireWire ports.

    • Assorted SCSI (SCSI50/SCSI68)

    • Assorted Audio

    • Video (ADC & DVI)

    • Networking (RJ-45 Ethernet/56k Modem)

    • Some later model MDD's (such as the dual 1.42GHz) Have a FireWire 800 Port Here:

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  2. Pull on the side lever and lower the side of the case.
    • Pull on the side lever and lower the side of the case.

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    • The ram is between the graphics card, and the CPU, and removal is simple. Push the tabs down on both sides, this will free the ram, then lift it out.

    • The MDD Uses A Maximum of 2GB PC2700 DDR,(512MB X4) and had 4 slots for ram.

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    • The AirPort card is located next to the graphics card.

    • If your computer has a FireWire 800 port between the FireWire 400 Ports and the Ethernet Ports then your computer uses an AirPort Extreme 802.11g Card (See Related Parts). If your computer has no firewire 800 port, then your computer uses an 802.11b AirPort PCMCIA Card (Also See Related Parts). Removal of both cards is pretty much the same.

    • First disconnect the antenna from the card, it may be helpful to use a spudger or flathead screwdriver.

    • Now, grasp the plastic tab on the back of the card and pull it out of the computer.

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    • The Airport 802.11b PCMCIA Card.

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    • The hard drive cages are located here.

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    • Cage 1

    • Start by removing this screw.

    • Remove the IDE ribbon cable from the motherboard.

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    • Now, remove the power connecton from the drives.

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    • Now, push this tab down, and pull the cage towared you.

    • Now, you can set cage 1 aside.

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    • Cage 2:

    • Remove this Phillips screw:

    • Disconnect this IDE ribbon cable from the logic board.

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    • It's likely that there is a cable clip holding the ribbon cable to the case.

    • To remove it, push the end, and it should pop up.

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    • With the clip free, pull on this tab, lift the cage up, until it clicks, and pull it away.

    • Now, set the cage on top of the CPU, and remove the power connectors.

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    • Once the cables are free, set the drive cage aside.

    • To remove the hard drives from the cages, remove the four screws on the sides of the cage that are connected to the drives, than slide the drives out.

    • The two cages are cross compatible and can be put in either rack.

    • The MDD does not have a 128GB drive limit like older macs, My MDD has 3 Drives (A 400GB Hitatchi Deskstar, 40GB Seagate Baracuda 7200.7, and a 30GB Quantum Fireball LCT).

    • Note the ID jumpers on the two drive set. One is set to Master, the other to slave. A single drive can be set to Cable Select.

    Thanks - excellent tutorial!

    Question: If you have a single internal drive, and a connected extrenal drive via firewire or usb, what jumper setting should be set for the internal drive and the external drive? Booting into Mac OS 9 natively (not via Classic) on the internal drive seems to be sensitive to the jumper settings and I’m having issues getting it to work.

    LTG Seb - Reply

    I ran my MDD with 3-750GB IDE HD’s. When they got flakey I replaced them with 2TB SATA drives in the back cage with a cheap SATA to PATA adapter and they formatted out to 1.8TB. I then cloned (CCC) the boot drive to one of the 1.8TB drives. It boots to the new drive and every thing seems to operate like normal. I don’t know how big we can go but we know that a MDD will handle at least 2TB HD’s and I have 5TB in my iMac 15,1

    Glenn Stettler - Reply

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    • Start removing the optical drive cage by removing the back cover.

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    • Now, remove the IDE and power cables.

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    • Remove these two Phillips screws:

    • Now, pull the cage away from the front until it is free.

    • Now, lift the cage out.

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    • To remove the drive from the cage, remove the four screws on the side of the drive, and pull the drive out of the cage.

    • My MDD has a 3rd Party 22X SuperDrive, for burning DVD's in Leopard (Thank You Generic Drive Support!)

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    • The Power Mac G4 MDD uses a Mac-Compatible AGP Graphics card with ADC, And DVI or VGA.

    • My mac has a NVIDIA GeForce4 Titanium with 128MB of video ram, this was an excessively large card, for some reason.

    • Start by removing this Phillips screw.

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    • Using a flathead screwdriver, spudger, or your finger pull this tab towards you, and lift the card out.

    • The "excessively large" NVIDIA GeForce4 Titanium 128MB. This was one of the most powerful cards on the market when this computer was released, now, there are flashed cards such as the Radeon 9700 Mac, but this is the most powerful AGP ADC supporting card, great for gaming, Photoshop, and other 3D intensive applications.

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    • The DVI And ADC Ports.

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    • The Power Mac G4 MDD Supports four PCI Cards, allowing for SCSI, sound, wireless networking (only AirPort compatible clones) USB, FireWire, etc. The PCI slots do not, however support PCI graphics.

    • Remove the screws for any occupied PCI bays.

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    • Once the screws are removed, pull each card straight up and out of the computer one at a time.

    • The Cards:

    • Adaptec SCSI 50-Pin

    • Adaptec SCSI 68-Pin

    • USB/FireWire Expander

    • M-Audio HD Sound Card

    • NVIDIA GeForce4 Titanium (Mac Edition) DVI & ADC

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    • Optical Fan:

    • Remove these two Phillips screws:

    • Now, slide the plate towards the case, and lift it up, and off.

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    • Once the cover is removed, disconnect the power cable and thread it under the dust shield.

    • Now, lift the fan straight up and out.

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    • System Fan:

    • Disconnect the optical drive IDE cable from the logic board.

    • Now, remove the system fan cable.

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    • Now, grab the system fan by the sides and pull it up, it should come free, the system fan is very large and loud, compared to standard sized fans.

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    • To remove the power supply connector from the motherboard, push at the top of this clip, and pull the connector off.

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    • Push on these two clips here to release the power cable.

    • Now, thread the power cable out of the small hole it comes through.

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    • Remove this Phillips screw:

    • There may be a small hex screw here on the back of the case, it must be removed if present:

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    • Now, slide the power supply towards the front of the case, and pull it out. It is a little heavy, so don't drop it on the logic board.

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    • The power supply has a 24-Pin connector with non-standard voltages, so dropping in a 24-Pin ATX power supply without modification isn't a great idea.

    • The power supply connector has a 25V lead to drive apple ADC displays, so though it is possible to modify an ATX power supply, it won't be able to drive ADC displays, just VGA, or DVI, though the computer will work fine (I've actually tried this).

    • It also has three 12V/5V rails to drive all six drives (four hard drives, two optical Drives) simultaneously. This is the only Macintosh computer other then the Mac Pro to support six drives.

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    • This is also the notoriously loud AcBel 400W "Windtunnel" power supply

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    • Now, remove these three Phillips screws:

    • As there are two Phillips screws well, there are two that you can see in the photo, but you want to remove the screws that are behind them.

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    • Now, lift the heatsink up off the computer, it is pretty heavy, because it's a giant block of aluminum.

    • Be careful when holding it, the edges can be sharp, making it likely to get cut if you hold it wrong!

    • As you may be able to tell, i have applied a replacement coat of Arctic Silver 5 to keep my MDD cooler than the stock paste, it really does a great job too!

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    • The incredibly large heatsink, this thing is 5 Lbs of solid aluminum. Just like every other part in this, and many other Macs, the heatsink is made by: ...you guessed it, Foxconn.

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    • The Powermac G4 MDD's, Guts Spilled On My Desk:

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    • The PowerMac G4 MDD Complete With Pro Speakers, 17" Studio Display, Mighty Mouse And Keyboard, Runs Leopard Server and Ubuntu 9 Beautifully.

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Chris Green

Member since: 10/11/2009

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One Comment

Any idea if that heatsink can be used for a dual 1.42GHz board or must I get the copper heatsink?

nirv - Reply

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