20" iMac G4 Mod - Updated for Ivy Bridge and Mountain Lion (In Progress)

[jberg44]

20" iMac G4 Mod - Updated for Ivy Bridge and Mountain Lion - Completed

I had previously posted my 20" iMac G4 Case Mod which used a Core i5 Sandy Bridge small form factor ECX board and ran OS 10.7 Lion. I have decided to do an updated version with an Ivy Bridge Chipset, HD400 graphics, and running 10.8 Mountain Lion, I have made significant headway and am using two different small form factor boards/systems and will incorporate the best one into the final build.

Board #1: Mobile Quad Core i7 Ivy Bridge EPI-QM77 Board running Mountain Lion 10.8This is the EPIC board, at 4.5" x 6.5", it is slightly larger than the ECX board, but much smaller than a mini-itx, and it fits easily within the dome. I used the Unibeast/Multibeast install method (Thank you again tonymac). Changing the SATA from IDE to AHCI was the only change I had to make in the bios, otherwise it installed natively. Interestingly, I had trouble getting the USB to function from a USB 3.0 port, but when I plugged it into the apple keyboard's USB via the USB 3.0 it worked fine.

I am still tweaking the multibeast settings somewhat, but will report them with final recommendations shortly. This build eschews the optical drive which was in my previous mod for the native PSU. Although this is cleaner as there is no power brick, I have mixed feelings about loosing the aesthetics of the drive. Its getting harder to justify what is really a cosmetic feature at this point. I am still trying to devise a use for this and to somehow incorporate a usb powered motor to open and close the door revealing a hot plug or extra ports. I will have to see what might be needed from a cooling perspective, but I may need to upgrade to a larger heatsink, but can not be sure until the computer is fully assembled.

This is likely the build I will keep as this board has everything I need, Core i7 Quad Ivy Bridge with HD4000 graphics, Enough USB 3.0 slots and 2 SATA 6.0 ports. Even a quality 7.1 Realtek Audio Chip is included.

Board #2:THE INTEL DC3217BY

On the forums I have seen successful builds using the sister model which has ethernet and two monitor support. This is the "higher end" model because of the inclusion of a thunderbolt port. With the help of mikeboss' tip (thank you mikeboss for saving me hours of frustration), to set the graphics to 128mb, this board was able to post. I did not go further as a mSATA is required and I did not have one large enough until now. I have installed this Crucial 128GB mSATA, as well as a broadcom half height wifi card. As this board is nearly identical, I suspect I will have similar success. The question will be the thunderbolt, which I am hopeful will work natively.

Thank you for reading, advise and suggestions are appreciated. Happy to answer any questions and will keep updating as I go.

 

[sonicseamus]

Just a suggestion, if you change the serial number in your smbios.plist to the original one on the iMac, you can get the about this mac picture, name and year changed to that of the iMac without changing the actual definition being used.

 

[jberg44]

Thank you! Would power pc serial numbers be included in mountain lion?

 

[sonicseamus]

Yep it should work fine!

 

[doctorevil30564]

I always liked these G4 Imacs, very unique design. subscribing to this topic, keep us updated with pictures and info as you have them available.

 

[jberg44]

Here is an update: I have decided to go with the NUC board, with a few exceptions, its very well suited for this project. In my previous ECX mod, the board only fit with the optical drive because I did not use the native PSU. Because I wanted to use the native PSU, I did not believe fitting the optical drive was possible, but with this board it looks like it is going to fit. This board fits into the slot left vacant by the 3.5" HDD (the mSATA is on the mobo itself). It pretty much fits into the grooves in the drive chassis requiring no alternation. It's quiet and low power and works great with mountain lion. With this fitting at the top of the dome, I should have even a little but more room for components than I did with my previous mod. This is because, there are less port extenders needed and no SSD is required at the bottom of the dome. It will still be tight, but I have some wiggle room to address the problems that this board does have.


1) Few USB Ports: A USB Hub is needed, but even a 4 port USB Hub leaves me with only 1 spare USB port, but solves the problem. The addition of another hub or a larger one is likely. A USB port is what activates a 5V switch which turns on the 24V line in the native PSU, I use the power and ground of the USB to supply 5V to the PSU.

2) No Power or Port for a Case Fan or Molex/SATA power for the optical drive:
The cpu has a directional fan on the heatsink and I did not want to remove it. A Case fan is needed in addition to the cpu fan. Apple's connectors and colors are completely backwards from industry standards (Black is 12V, Red is Ground and the fan out is a 3pin Male connector, not Female). The fan is also somewhat loud and old, so I replaced it. I bought a Antec 92mm fan that had a molex out (there is no case fan output on the board). There is a sense pin that I won't be using. Because I won't have software fan control, I got a model with a 3 speed setting. I put it on medium to reduce noise and may extend the controller to the back ports or simply leave it on this setting.

While 12V are readily obtainable from the PSU, the problem is that the PSU is always on. So, the fan will spin as soon as the computer is plugged in, no matter if the computer is on or not. As the computer does not have any 12V out, I will have to use some kind of switch. Luckily, the PSU comes natively with a "switch". The PSU relies on the motherboard to downconvert 12V to 5V then feed 5V back to the PSU to turn on the 24V line that powers the monitor's backlight. Although there are many other ways to do this, I went with what I had available. The optical drive requires 12V and 5V in either a molex or SATA power connector. Luckily, I had a very small 20 pin PICO power supply with a WIDE INPUT range up to 24V. (Not all PICO PSUs can accept 24V, may sure before you connect). I spliced the PWR input to the Green wire of the PSU (24V) which connects to the Inverter Wires as well. I connected the ground to a native PSU ground. I then jumped the PICO PSU. This produces the necessary 12V and even a 5V and has both a Molex and SATA power cable out. I connected the Molex to the Fan (you only need the 12V line and ground), and the SATA to the optical drive. Now the peripherals will only turn on when the motherboard itself is turned on. The DVD Burner is connected to the mobo is via a SATA to USB 2.0 adapter cable.

3) Power Switch: I did not want to damage the board, so I simply threaded small wires between the onboard switch and its solder points. This was then wired to the case switch at the bottom of the dome. These can be easily removed in the future if this board is ever repurposed. In addition this does not effect the functionality of the original switch in any way.
4) Audio: I am sticking with the Turtle Bay USB Audio solution from my last mod. This allows for a standard 3.5mm audio jack out and also supports a 3.5mm Microphone in. I have it wired to the microphone in the LCD housing.

5) Bluetooth: I have not found a half height mini PCI-E that supports Wifi and Bluetooth with Mac OSX. So, I am simply going to keep a small USB bluetooth solution.

6) Power for the motherboard: The NUC requires 19V at 3.7A and the PSU is only supplying 12V (can't use the 24V because its only on with 5V from the motherboard). Luckily, 19V is the typical notebook operating voltage and therefore upconverters are available. Though there is a much smaller selection than for more common voltages (24V, 12V, 5V etc). I got one on ebay for $20. Its relatively small and is a 12V DC to 19V DC upconverter at 4A.

Obviously, there is a lot of cable management to do. This will get much simpler once connections are directly soldered (connectors removed and alligator wires eliminated). As I technically have more room at the bottom of the dome than the previous mod (also had a DC converter and a PICO PSU to deal with), I do not believe this will be difficult to fit. The wire management, however, may be more involved.

Currently, I have completed a fit test for the motherboard with ports in the case, and so far so good. The computer runs great and I'll hopefully complete this soon.

 

[mightydood]

Really amazing! Looking forward to how it all goes!

 

[rick26]

This mod is amazing! but what a cable mess! haha but i love it,

Good luck! now i really want an imac G4 to by seeing this!

Rick,

 

[spence4]

Hey Jberg,

Very nice work with the NUC and iMac. I have a couple questions for you. How do you connect the iMac monitor to the NUC? Will this work just as well with a 15 inch iMac G4? My brother has an old iMac in nice cosmetic shape and while I would love the larger widescreen version, you cannot beat the price. Please let me know. Thanks.

 

[jberg44]

20" iMac G4 Mod - Updated for Ivy Bridge and Mountain Lion - Completed

This board works great for this mod. I would probably recommend the less expensive version of the NUC, as the thunderbolt port is not even in use. The only thing I have left to do is create port casings on the back. The back ports include the AC plug (all native), 4 USB ports (one with a small Bluetooth adapter), a 3.5mm audio jack, and a "fake" Firewire 400 port. The reason the port is fake is that the only thing it is connected to is a 12V Molex and ground. It is there to supply the needed power via firewire cable to the griffin ifire audio amp/adapter. This allows me to use the original apple pro speakers without needing an additional powersource.

I was able to resolve all the issues noted in my previous post and both the 12V to 19V upconverter to power the NUC as well as the Wide Input PSU worked great. The SATA to USB DVD burner works as expected and using KeyRemap4Macbook, it ejects with the keyboard shortcut key. Changing the serial number in the smbios.plist did not alter the information or picture in the identifier for me. But, renaming the 20" iMac G4 icon as the mac mini in the resources folder changed the image and the name to iMac.

Everything seems to work great with Mountain Lion except S3 sleep. I'm going to work on it, but in the meantime S1 sleep works fine. I am truly amazed by how well this worked out and have to say the Intel NUC and the iMac G4 20" are a perfect match. I've included a few pics and hope to have a video up soon. Thanks for the advise and encouragement.

Spence4 - all the iMac G4s use TMDS signaling (HDMI/DVI) instead of traditional LVDS so they can all be made to accept a regular DVI/HDMI signal with some pin rearrangement, a few tricks, and a highly recommended DVI adaptor. I have instructions for the 17" and 20" on my blog (dremeljunkie.com) but have never done the 15" myself. Another modder did the 15" and with his permission I have posted his pinout on my blog as well. Hope this helps. JB