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Installing Powerlogix 1.5GHz 7447A CPU Upgrade for Power Mac G4 Cube

May 8, 2008 4 comments

I bit the bullet yesterday and upgraded my Power Mac G4 Cube from its original 450MHz processor to an overpriced 7447A Power CPU in the form of a Powerlogix CPU Upgrade.

First up, I had intended to purchase a chip with a VRM bypass but when it arrived, I found that I’d mis-ordered and got a vanilla version without.

I checked the website more closely and yes, indeed the version I had ordered did not have the VRM.

I would have sent it back, but unfortunately, I ordered it from OWC in the US, so that’s not going to happen.

Here are some extra hints if you want to replace your CPU with a Powerlogix one. These are not complete instructions in and of themselves.

Before you start, watch the video and print and read through the instructions. They are clear on most counts but I found a few areas lacking.

Here I’ll list a few of the difficulties I faced while also listing the outline of the instructions

Firmware Update
 
(in a nutshell) 

  • Insert the CD with the Cube powered up. Then shutdown the Cube
  • Now hold down the programmers button and keep it held until the power light flashes rapidly then press and hold C until the firmware screen appears.
  • At the menu
  • Press 4
  • Wait for the process to complete.
  • Press 5 if you use OS 9.

 Now this bit was a bit worrying, nothing was mentioned what to do after the above steps. 

  • Just press the option to shut down the Cube
  • Proceed with the disassembly.

Graphics Card and VRM

  • Ground yourself.
  • Remove all cabling.
  • Pop the chasis.
  • Remove the top plate.
  • Be careful with the power connector between the top and the chassis. It’s quite short.


    fig 1

    You do NOT need to disassemble the whole chassis in order to remove the CPU.

    • Just turn the cube on its side (GFX card up) and remove the two posts. Remember which way they go, they look very similar but won’t fit if you get them in the wrong place or the wrong way around!


      fig 2

      • On this side of the motherboard, you only need to remove three screws. 

         
        fig 3

        Removing the Video Card

        The first real challenge you will encounter is removing  the video card. The cube is tight and the card is connected to a riser from the motherboard rather than directly to the motherboard itself.

        • MAKE SURE YOU’VE REMOVED THE TWO SCREWS that hold the GFX card to the frame. They are located on the base of the Cube and flank the VGA and ADC connectors.
        • Remove the Video Card and Riser card together. It’s not possible to remove the card by itself.

          The main difficulty is that the ports are stuck through holes in the base, which prevents you from lifting the GFX card and riser vertically, you have to lift just the point shown below.

          Don’t worry, the connector is quite tough and the angle won’t break any pins or edge connectors if you are careful.

          Try not to lift the GFX card out too far at first and be careful of the wires connecting the GFX card to the motherboard.

          If you are having difficulties with the GFX card assembly, you might want to remove the VRM first, which is considerably easier to get out.


          fig 4

          The black connector shown below comes off easily. Just push down on the protruding part of the clip like a clothes peg and pull the clip out.


          fig 5

          Try as I might, I was unable to remove the brown connector shown in the picture above.

          Instead, I just pulled the GFX card from the riser and hung the riser over the side of the chassis, out of the way, making sure the light grey wire (shown towards the right of the above photo) was OK.

          Removing the VRM

          Once the GFX card is out of the way, it’s relatively easy to remove the VRM module (That’s the other riser on the right), opposite the RAM slots.

          Since I had some difficulties removing the GFX card, I removed the VRM first, to give me more space, but the principle is the same.

          There is a little grey catch toward the back of the unit, next to the VRM module.

          • Use a screwdriver to release it by sliding the catch to the left (if oriented as shown below). Note that there is very little feedback from the clip. Just push it back gently while pulling the VRM up and out, vertically.


            fig 6

            Extracting the motherboard

            In order to extract the motherboard, you need to ensure you have done all of the following:

            • Removed the GFX card.
            • Removed the VRM.
            • Unscrewed the two motherboard screws along the front edge of the board as shown in fig 3.
            • Removed the “unique screw” from near the VRM. (fig 7)
            • Removed the “long screw” from near the memory slots. (fig 7)


              fig 7

              • Unscrew the three, spring-loaded screws from around the large grey chip in the middle of the motherboard and pull them out vertically. Mine were quite stiff and required wiggling to get them out.


                fig 8

                Before you can extract the motherboard, it has to be released from the big central heatsink beneath it, which due to heat and time will have fused itself to the CPU’s heatspreader because of the thermal sheet between them.

                I found the method used to separate the two from each other very difficult. Perhaps because my screwdriver was too big. I couldn’t get it between them to start prying them apart.

                • I started from the corner by inserting my screwdriver and twisting gently. The heatsink came away easily enough.


                  fig 9

                  Once you’ve lifted the motherboard away slightly from the big heatsink, pull it towards you, away from the bottom of the case, with all the ports on it and parallel to the central heatsink.

                  Remember, there are two posts guiding the rear of the motherboard. If you lift the motherboard rather than pull it towards you, you risk the motherboard’s supporting corners being snapped.

                  Note that the ports on the bottom of the Cube are pushed through holes in the base. These holes are sealed with a kind of metallic springy foam, probably for shielding.

                  You will have to pull the motherboard away from the base with a little bit of force, since the springy foam may have got quite hard with time.

                  Replacing the CPU and heatsink

                  • Remove the old CPU carefully.
                  • Replace with new CPU.

                    This next part is optional, but I hightly recommend it

                    • Scrape off the old thermal compound from the back of the big black central heatsink.
                    • Apply a thinly spread layer of heatsink compound to the new CPU’s heatspreader.


                      fig 10

                      Install the base fan – DO NOT FORGET. THIS IS NOT OPTIONAL. Running the upgraded Cube without a fan will destroy it!

                      Now follow the instructions and put everything back together.

                      Once you hear the Apple Bong, CHECK THAT THE BASE FAN IS ROTATING AND BLOWING AIR UPWARDS. IF THE FAN FAILS, SO WILL YOUR CUBE.

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                      Categories: Mac, mods, Technology Tags: , , ,

                      128Gb+ Large HDD (LBA48) support on the G4 Cube with Leopard, for free.

                      April 27, 2008 8 comments

                      It’s possible to access the entire space of any large hard disk without drivers, that means without the need for the $25 Speed Tools ATA Hi-Capacity Support Driver. This also means that Leopard will work, too.

                      With the magic of the Open Firmware, as with the Open Firmware fake CPU speed hack, it’s possible to hack the Open Firmware to enable large disk support, otherwise known as LBA48.

                      I have only tested this with Leopard and Tiger, so I can’t vouch for earlier OS-X builds. however, note that this DOES NOT WORK FOR OS9. For OS9, you will still need the speedtools driver available here:

                      This time, however, we need to write this to the non-volatile RAM so that the changes aren’t lost on reboot.

                      • Reboot or Power up your Cube
                      • Hold down Command + Option + O + F simultaneously as soon as the reboot starts.

                      You should now be at the Open Firmware prompt. Note that this is NOT the BASH prompt, so don’t try anything here.

                      • Type in the following, exactly. Please note that the Underscore “_” is used to indicate a space.
                      nvedit
                      dev_hd
                      dev_..
                      "_"_"_lba-48"_property
                      device-end
                      • Press Ctrl+C to exit from nvedit.
                      nvstore
                      setenv_use-nvramrc?_true
                      reset-all

                      That’s it. Now boot up and go to “About My Mac” to confirm the disk size.

                      If your disk was already formatted, it will have its original 128Gb partition and a region of inaccessible space at the end. It’s probably easiest to reformat the disk with a new partition scheme, unless you have some terminal disk utility or related tricks up your sleeve.

                      • This hack will last until you reset the NV RAM (P RAM).
                      • Similarly, if you hose your open firmware settings, use this fact to your advantage, perform a PRAM reset and start again.

                      If you do repartition the disk, it’s probably wise not to cross the 128Gb boundary with a partition, in case you ever have to reset the NV RAM, in which case you’ll only be able to access the first 128Gb of the the hard-disk. By splitting the disk at 128Gb, you’ll ensure that only whole partitions are visible and any partition after the 128Gb will be entirely invisible.

                      In my case, I made a front partition of 128Gb, and the remaining 30 something Gigs into an extra partition for temprorary files.

                      Thanks to the Cube Kaizou (Cube Mods) page on Studio Milehigh (!!!) homepage. Apparently his own Cube died at the end of April last year but he has left his legacy of Cube update experience online.

                      Categories: Mac, mods, Tech Tips, Technology Tags: , , ,

                      Adding a thermometer to the G4 Cube.

                      April 23, 2008 Leave a comment

                      After replacing the original 20GB drive with a nice new one, I got a little concerned about the temperature. I’ve installed a 1200 rpm, practically silent (19dB) fan in the base and wonder if it’s enough to offset the heat generated by the 7200rpm Hard Disk. 

                      So, for the the third and final installment on modestly modding my Power Mac G4 Cube, I’ll show how and where I added a thermometer to measure the drive temperature. This should take about five minutes.

                      Get yourself a nice digital thermometer with a surface contact probe, like this:

                      Contact Sensor Digital Thermometer

                       

                      The temperature probe should be small enough to fit through one of the holes in the bottom of the Cube’s casing:

                      Thermometer Wire

                      Opening the case:

                            First make sure you have the thermometer, some aluminium tape and enough room to work on,  i.e. a flat, clear surface within easy reaching distance.

                      • Unplug the Cube and invert it. Take care not to scratch the machine’s plastic case. I inverted mine onto a pillow.
                      • Push the rectangular, inset bar located on the upturned base in firmly, until you hear it click. Now release it. The handle should pop out.
                      • Use the handle to lift the chassis out of the upturned case. If this is the first time it has been removed, it might take a little teasing to get things moving.
                      • Lift the chassis out vertically, taking care not to scratch the insides of the case with the metal corners of the chassis. The chassis has no sharp corners so this is not a serious issue. Still, it would be a shame to scratch it.
                      • Now place the chassis down on a flat, clear surface. Take care not to damage the sensor on the top of the unit (probably facing downwards since it’s the side opposite the handle).
                      • Push the handle in all the way and let go. It should stay in place.
                      Connecting the Thermometer
                      • locate the side of the Cube where both the RAM and the HDD are visible.
                      • Push the probe up through a hole in the bottom of the case. Somewhere near the BIOS battery is a good area.
                      • Pull in as much wire as required and bind the wire tightly with a wire tie to one of the internal posts. There is a space above the Airport sensor on the the side, perfect for this purpose.
                      • Tape the sensor to the side of the drive firmly with aluminium tape.
                      Fan on side of Mac Cube
                      Now reassemble the computer.
                      I found that when actively using the Cube, the drive would reach about 40 degrees when active. A lot cooler than the 55 degrees it used to reach before installing the fan.

                       

                      Categories: Mac, mods, Technology Tags: , , ,

                      Installing a Large 128Gb+ Hard Disk in the Mac G4 Cube

                      April 21, 2008 1 comment

                      I’ve been running my G4 cube with a large hard drive since just after I bought it in May, 2005. I thought it was time to show you the quickest way to replace the drive in 10 minutes, without any major disassembly.

                      The Cube is a product of its day and I’ve had mixed results with high capacity drives in my Cube, including drives that “should work”.

                      Firstly, bear in mind that if your drive is larger than 128Go (A Go “Giga Octet” is the new way of saying GB when you mean 1024x1024x1024 bytes rather than 1,000,000,000 bytes that the drive manufacturers use to inflate their drive sizes 128Go is about 132GB) , you’ll need to purchase the

                      Intech ATA Hi Capacity Driver for Mac OS X

                      Or else your computer will only recognise the first 128Go, regardless of the drive size. I’ll discuss this in a later post.

                      Update: You can use an Open Firmware hack to achieve the same thing. Read here.

                      You’ll need a set of Torx drivers for the star shaped “security” screws. Sizes T8, T10 and T12 should do the trick. You will also need a medium sized pair of pliers for some minor and painless case modifications.

                      Opening the case:

                             First make sure you have the fan, the torx drivers and enough room to work on,  i.e. a flat, clear surface within easy reaching distance.

                      • Unplug the Cube and invert it. Take care not to scratch the machine’s plastic case. I inverted mine onto a pillow.
                      • Push the rectangular, inset bar located on the upturned base in firmly, until you hear it click. Now release it. The handle should pop out.
                      • Use the handle to lift the chassis out of the upturned case. If this is the first time it has been removed, it might take a little teasing to get things moving.
                      • Lift the chassis out vertically, taking care not to scratch the insides of the case with the metal corners of the chassis. The chassis has no sharp corners so this is not a serious issue. Still, it would be a shame to scratch it.
                      • Now place the chassis down on a flat, clear surface. Take care not to damage the sensor on the top of the unit (probably facing downwards since it’s the side opposite the handle).
                      • Push the handle in all the way and let go. It should stay in place.
                      • Turn the case, so that the sensor is now facing upwards.
                      Chassis exposed
                      Removing the drive heatsink:
                      • Locate and remove the three Torx bolts which hold the drive hatsink in place as shown above. Note that the bolts are captive, and as such do not actually come out. This is a great Apple design point, since it stops the bolts from falling into the machine!
                      • Now lift out the heat sink itself.
                      Lifting out the drive heatsink
                      Removing the drive:
                      • Locate the airport card flap on the side of the unit.
                      Opening the Airport door
                      • Open the Airport door. It will swing out. Don’t worry, it’s well hinged and won’t fall off!
                      • Remove the drive power connector – Mine was stuck firmly and required pliers to release it!
                      Remove the power connector with pliers
                      Removing the drive power connector
                      • Now remove the ATA connector.
                      Removing the drive\'s ATA (data) connector
                      • The drive should now slide out from the opposite side of the chassis.
                      Sliding out the drive
                      • Remove the guide rail from the side of the drive.
                      Remove the guide rail from the side of the drive
                      Replacing the drive:
                      • Don’t forget the plastic drive guide rail
                      • Slide the drive back in. 
                      • (Optional) You may want to coat both sides of the three steel posts which hold the drive with a drop or two of heatsink compound, since new drives run much hotter than the old 20GB drive that was in there and every bit of cooling will help.
                      Add a few drops of heatsink compound to the drive supports
                      • Replace the bolts which hold the heatsink.
                      • Replace the data and power connectors.
                      • Close the Airport card door. Make sure the airport antenna cable  is taped  firmly to the door if you don’t have an Airport card installed.
                      • Put chassis back in case, connect and power up. 

                       

                      Categories: Mac, mods, Technology Tags: , , ,

                      Installing a fan in the G4 Cube

                      April 18, 2008 2 comments

                      Many Mac purists out there will shake their heads and disagree vehemently, but with spares for the remaing cubes starting to thin out, a fan is essential in keeping your cube healthy, and I heartily recommend one to anyone who uses their cube for more than a couple of hours a day.

                      The Mac G4 Cube was designed to hold a fan. Even though in it’s original incarnations (450MHz and 500MHz varieties), there was no fan installed, the case itself has a place to hold an 80mm fan of about 20mm thickness and with a little effort, one can crowbar a 25mm thick fan in for more effective cooling.

                      Be careful when selecting the fan. The one I bought was a silent, solidly built one which had supporting tubes around the corner mounting holes. It seemed like a good idea at the time. However, these turn out to make installing the fan without disassembling the whole case impossible. A lighter fan without supports on the corners would have been much easier to install. In any case, I used a hacksaw and cut two adjacent supports along the edge which eventually ended up towards the back of the Cube.

                      Three common types of fans

                      I bought myself a nice, quiet 80mm x 25mm 1900 RPM fan. They tend to be about 3~6db quieter than 20mm fans which push the same amount of air. It came with 3 wires, red, black and yellow

                      Replacing the fan is actually a little more time consuming than replacing the hard disk, but not really much more difficult.

                      You’ll need a set of Torx drivers for the star shaped “security” screws. Sizes T8, T10 and T12 should do the trick. You will also need a medium sized pair of pliers for some minor and painless case modifications.

                      Opening the case:

                            First make sure you have the fan, the torx drivers and enough room to work on,  i.e. a flat, clear surface within easy reaching distance.

                      • Unplug the Cube and invert it. Take care not to scratch the machine’s plastic case. I inverted mine onto a pillow.
                      • Push the rectangular, inset bar located on the upturned base in firmly, until you hear it click. Now release it. The handle should pop out.
                      • Use the handle to lift the chassis out of the upturned case. If this is the first time it has been removed, it might take a little teasing to get things moving.
                      • Lift the chassis out vertically, taking care not to scratch the insides of the case with the metal corners of the chassis. The chassis has no sharp corners so this is not a serious issue. Still, it would be a shame to scratch it.
                      • Now place the chassis down on a flat, clear surface. Take care not to damage the sensor on the top of the unit (probably facing downwards since it’s the side opposite the handle).
                      • Push the handle in all the way and let go. It should stay in place.
                      • Turn the case, so that the sensor is now facing upwards.
                      G4 Cube and Fan

                      Opening the chassis

                      In order to put a new fan in without a complete disassembly, it is necessary to remove the optical drive.

                      • Remove the top plate by taking out the four corner bolts and two bolts on either side.
                      Remove these eight bolts
                      • Lift off the top, slowly and remove the small cable which connects the power sensor to the chassis.
                      • Place the top panel somewhere level, avoid touching the sensor.
                      • Now slide the plate with the orange spot on it slowly up and out, revealing the optical drive.
                      Removing the optical drive cover
                      You should now see the drive exposed as the picture below shows. 
                      • On either side of the drive, there are some screws, holding it in place. Remove these screws on the sides of the optical drive to release it.
                      • Slide the drive upwards and remove the power and ATA cables from the connectors.
                      Removing the optical drive
                      • The drive can now be removed, revealing the gap at the bottom of the case for the 80mm fan.
                      Space for the fan
                      Installing the Fan
                      • In order to slide the 25mm fan into the case without disassembling the whole thing, we need to bend the fan supports out to the sides until they allow the fan to slide in.
                      Bend the fan supports
                      • Note that there are two further holders at the rear of the case which may prevent your fan from fitting.
                      • If your fan has corner posts around the holding bolts, remove two of them to allow the fan to slide into place. 
                      Three common types of fans
                      • Bend the supports back around the fan to ensure a snug fit, as shown in this example picture below.
                      Fan support bent around to hold the fan
                      • After playing around with the supports for a bit, I taped around the fan with duck tape after breaking the two back posts. This also helps reduce vibration noise, but this is not necessary.
                      Connecting the fan to the power

                      It’s now time to connect the fan to the power supply. We will use the optical drive’s power supply which we have at hand since we removed the optical drive.

                      • Remove the little cover from the back of the optical drive’s power connector.
                      • You should see four cables leading into the connector.
                      Connector Closeup - after removing cap

                      This big connector has the ability to generate 3 different voltages, 5v (slowest), 7v and 12v (fastest). Depending on your noise tolerance and the power and voltage rating of your fan, you may find any one of these three voltages suitable. This I will leave for you to experiment with.

                      Note, if your fan has three wires, one of them is unnecessary for this modification. You will have to determine which two wires (usually red and black) are the power wires and which one connects to the sensor.

                      The table below shows how to harness any of three voltages from the optical drive’s chunky 4 pin power connector. 

                       

                      Fan Wire 1 (Black)

                      Fan Wire 2 (Red or Yellow)

                      Fan at 5V

                      Molex Ground (Black)

                      Molex +5V (Red)

                      Fan at 7V

                      Molex +5V

                      Molex +12V (Yellow)

                      Fan at 12V

                      Molex Ground (Black)

                      Molex +12V (Yellow)

                      For example, to run the fan at 7V, connect the fan’s black wire to the +5V (Red) connection and the fan’s red/yellow wire to the +12V (Yellow) connection. You can connect the fan’s RPM wire directly up to the motherboard. Unfortunately, on the Mac, the wires are all black! Check the photo to confirm the voltages.

                      Connector Voltages

                      • Cut the power cables of the fan to a decent length, you won’t need the connector. You can discard the sensor wire on a three wire fan.
                      • Use a knife or other tool to push the cables strongly into the drive’s connector without damaging the metal “blades”. These blades should cut through the rubber insulation on the cable and create a connection with the copper wire itself.
                      • If the cable comes out, your fan will stop. This will be very difficult to spot later, unless you install a fan with an LED or other indicator, so confirm that the cable is tightly held before reassembling the computer. 
                      Closeup of a connector with fan connected.
                      • Don’t forget to replace the plastic cover.

                      Putting things back together

                      • First the optical drive’s data and power cables.
                      • The optical drive’s holding screws.
                      • The power button’s wire connecting the top plate to the chassis.
                      • The chassis top plate with its 8 screws.
                      • Upturn the chassis carefully and pop out the handle
                      • Carefully return the chassis to the case, making sure not to catch anything, and push the handle in all the way until it clicks.
                      • Turn the computer over, connect it up and restart.
                      • Confirm the fan visually, by listening or by holding your hand over the top vent.

                      Congratulations, your Mac G4 Cube just got even cooler!

                      Categories: Mac, mods, Technology Tags: , , , ,

                      Upgrading iMac 15″ flat panel (iLamp) Hard Disk, DVD Drive and Memory to the full 1GB

                      March 20, 2008 1 comment

                      I was thrilled to see just how well Leopard ran on my new 700MHz iMac 15″ flat panel LCD with the user upgradable RAM increased to 640MB and the stock 40GB hard disk.

                      So, I am really looking forward to seeing the performance and how the thing performs with a full 1GB of RAM (considered minimum for OS X 10.5 Leopard to run smoothly. I suspect that it will be 100% usable, not a “poor” or “barely ok”, but a full on “nice” or at least, “not too shabby.” 

                      Firstly, You will need a nice set of tools to get inside the iMac, it’s a bit of a fiend to open, along the lines of the Mac Mini, but with more screws! Not impossible, but not trivial.

                      First Up, make sure you have all the components you need

                      • 3.5″ PATA (Ultra ATA 66) HDD. There is no space for a SATA-PATA converter, so get the real deal.
                      • A Mac Compatible DVD Writer (preferably one with iDVD support).

                      NOTE: The DVD writer should be less than 19.5cm deep since that’s the size of the drive that’s in there. The tray bezel should also be removable.

                      • 512MB, PC133 (133MHz) 168 pin DIMM.
                      • 512MB, PC133 (133MHz) 144 pin SO-DIMM 

                      Before you start make sure that everything is ready:

                      • YOU WILL NEED SOME HEAT SINK COMPOUND (Thermal paste).
                        I’m shouting this because this is easy to overlook and WILL turn your iMac into a paperweight if you forget it.
                      • A set of Torx drivers, a number 10 and a number 15 should do the trick, but don’t quote me on that! Better off having a whole set from 6 to 20.
                      • A Plus head screwdriver. I have no idea what size, just look at the screws and be the judge 🙂
                      • A wide open, well lit space to work, covered in a soft duvet, pillow or stack of towels.
                      • Somewhere to earth yourself or better yet, a grounding strap.
                      Prepare your iMac for surgery:
                      • Unplug your iMac completely.
                      • Clean your iMac. Stray dust WILL somehow find a way to scratch your screen at the first opportunity.
                      • (optional) You might want to wrap the screen in a soft, clean towel and pin it with safety pins.

                       Removing the user accessible parts of the iMac.

                      • Unscrew the base screws with the plus-head screwdriver.
                      • Remove the RAM and Airport card, if present.
                       
                      Removing the base
                      • Remove Torx bolts holding base together.
                      Remove base screws
                      • Now remove the base, carefully, prising the bottom off. 

                      Important: Try not to twist or bend the base in relation to the top. Work your hands around the base, gradually easing the base away from the top. At all times, keep the base parallel to the top until it is clear of the connectors.

                      Pull the base off the iMac
                      • Now the base is off, you may, depending on the way your iMac is being supported, need to detach some or all the cables which hold the base to the top. There are six cables, see the diagram below.

                      Disconnect iMac base

                      Make sure you can remember where each cable goes. Also, the green earth cable on the left hand side is secured to the top with a Torx bolt that needs to be removed.

                      Replacing the internally installed (non-user-serviceable) RAM

                      The RAM slot is visible at the bottom of the above picture and can now be replaced.

                      Make sure you replace it with a decent, “full-size” (desktop) 168pin 133MHz SDRAM chip. 100MHz chips tend to cause kernel panics, avoid them!

                      • Push the two cream coloured tabs out and down and the DIMM should pop up. Pull it out vertically.

                      Replacing the internal, full sized DIMM

                      • Now might be a good time to use an air blower and clean out the RAM slot.
                      • When replacing the DIMM with a new one, make sure you push it in vertically, all the way to the bottom. The two cream coloured tabs should automatically pop into place.
                      • I’ll repeat the bit above, make sure you push the RAM in vertically, all the way to the bottom. If you don’t you’ll be reopening your case again sooner than you’d like.

                      Removing the drive assembly.

                      Next we are going to remove the drive assembly which holds the hard disk drive and the Combo DVD Drive.

                      • Remove the copper tape that holds the electromagnetic shielding from the front of the drive and the two bolts shown below.
                      • Gently pull the shielding away from the top and put it aside.

                      Remove iMac EM shielding

                      • Now remove the four bolts that hold the drive assembly in place.
                      • Make sure there are no cables tethered to the drive assembly. If there are, you will need to cut the cable-ties and release them.
                      • Lift the drive assembly away from the top.

                      Remove iMac drive assembly

                      • Once the drive assembly is out, remove the power connectors from both the HDD and DVD.

                      The data connector is lodged between the two drives and cannot be removed.

                      The HDD is covered with a sticky backed film, probably an interference reducing tactic. This film will have to be removed before we can remove the HDD from the assembly.

                      • Carefully peel off the paper.

                       

                      Remove sticky paper cover

                      •  Remove the eight bolts which hold the hdd

                      Remove HDD and DVD bolts

                       

                      • Lift out the HDD
                      • Slide out the DVD drive, connector first (i.e. backwards)
                      • Make note as you do so where the fronts and backs of of each drive sit!

                      Disassembly Complete:

                      Read the remainder of this post for some critical tips and then work back through this post in reverse if you need to look at the photos.

                      • Replace the drives in the assembly, making sure the ATA cable is between the HDD and the DVD drive before tightening anything.

                      Drive assembly checks:

                      Before reassembling, confirm the following:

                      • HDD is set to Master and the DVD is Slave or as Apple recommends, use Cable Select for both drives – If this is not done, you will find one or both of the drives inaccessible.
                      • The drives are aligned properly and are the right way around!
                      • The DVD drive fits – Some are deeper than others!
                      • Before you screw the drive assembly into place, make sure you have reattached the ATA connector and the power connectors to both drives. Trying to reconnect the cables after bolting the drives in place is a futile waste of time. (Talking from experience!!)
                      • Make sure the appropriate wires run behind the drive assembly before the drive assembly is replaced, since routing the wires around the side may interfere when closing the case. 
                      • The DVD bezel on the tray is small enough to fit though the white drive flap on the front of the iMac.

                      You may need to remove the new DVD drive’s whole front plastic panel and/or the plastic bezel on the front of the drive tray.

                      • You will need to remove the bezel first: use a pin, piece of stiff wire or a paperclip to poke the little hole at the front of the drive and release the tray. Behind the lip of the tray, there should be a couple of clips holding the bezel to the drive tray.
                      • Now, the drive front panel can be removed (usually, depending on your drive). There are typically four to six holes in the metal casing of the drive, near to the front panel, form which protrude short plastic posts. Pushing the posts in with a screwdriver one by one should release the front of the drive.

                      Reconnecting everything:

                      The CPU heatsink is connected to a heatpipe which runs along the bottom of the case from the CPU to a junction, which transfers the heat from the CPU into the upper-half of the base to be cooled by the top mounted fan.

                      iMac Heat Pipe Bottom

                      • Scrape of the old heatsink compound and thoroughly clean and polish the post without filing or reducing in any way. You may need acetone or metal polish. A plastic scraper may also help remove the old gunk which may have hardened due to heat.

                      iMac Heat Pipe Top

                      • Do the same for the top part of the junction.
                      • Apply a thin, neat coating of heatsink compound (thermal paste) to either one -not both- of the posts.
                      If you do not clean the junction properly or forget to apply the heatsink compound, your iMac will freeze, crash and perhaps suffer irreparable damage due to the CPU overheating.
                      • Now connect all the wires back up. 
                      • If necessary, restrain the cables against the side of the drive assembly to prevent from getting trapped when resealing the base.
                      • Align the two halves of the case.
                      • Ease the base on, making sure the rear connector is fitting snugly before tightening any bolts.
                      Do not attempt to run the iMac until the four base bolts are back in place. One of them is used to squeeze the two halves of the heatpipe together, without which the heat won’t transfer away from the CPU and you computer will malfunction.
                      Mission accomplished.
                      Categories: Mac, mods, Technology Tags: , ,

                      Upgrading iMac G4 to 640 MB.

                      February 12, 2008 Leave a comment

                      The iMac G4 is unique, as far as I’m aware, in that it has two memory slots which take different types of memory. One slot is easily user accessible with nothing more than a screwdriver and takes a 133MHz laptop SO-DIMM, up to 512MB.

                      The other comes factory preinstalled (in this case with a 128 MB, 133MHz DIMM), but is much harder to access, requiring disassembly with a set of Torx (star) drivers.

                      Upgrading to 640MB, then, is a simple task requiring about 5 minutes.

                      You will need:

                      • A large area with soft padding to support the iMac in a lying down position.
                      • A small, cross-head (plus) driver.
                      • A branded 512 MB, 133 MHz, SO-DIMM for a laptop, preferably with a compatibility replacement guarantee, should things go wrong.
                      let’s get started:
                      • Turn the iMac on its side. Take special care not to scratch the screen or the computer’s plasic casing.
                      • Locate the four screws on the base and unscrew until loose.
                      iMac, getting the base off
                      • Carefully remove the beautifully crafted aluminium base plate, revealing the RAM slot.
                      • Ground yourself on something metal, like a metal door sash, a large metal desk or the kitchen sink.
                      • Carefully insert the 512MB RAM stick in the slot at about 30 degrees angle from the base. Push the long edge very firmly, sliding the chip into the slot. 
                      With iMac open, insert the RAM.
                      • Make sure the gold contacts are well in contact with the slots pins. When you are sure it is seated firmly, press down on the flat side of the chip until it is level with the base of the computer and the little tabs on either side clip into place.
                      Inserting the RAM properly
                      • Make sure the chip is held firmly and the clips are properly clasping the chip.
                      • Replace the lid.
                      That’s it. Power on and check the Apple menu, and About This Mac to confirm the memory.
                      You should test the system over night with a memory checker. I recommend:
                      Rember by Kelly Computing
                      You should now have an iMac with 640MB of RAM.
                      Categories: Mac, mods, Technology Tags: , , ,