iMac G4 Mod Alternatives
Nick, I saw this post and thought I may be able to help. I have spent a significant amount of time modding the iMac G4 because I like you was always intrigued by the design. I have tried almost every conceivable variation (different mobos, lcds, monitor casings etc) over the past few years. The reason I liked this project is that its been a fun challenge, but that said, the iMac G4 dome is an inhospitable place for a computer. The original components (except the drives) were specifically designed to be used with this case and to be convection cooled. Putting something else in this case is literally a square peg in a round hole. A mini itx can be wedged in (barely), but when I did this it didn't make it to the 3rd boot before it started giving me problems. There are 3 key reasons for this:
1) Space - The round design and protrusions from the metal faraday cage inside give you much less room then you realize. Many ports on a mini itx board would be inaccessible as the connectors would not be able to fit. A mini itx with heatsink would use up all the available space, but you still need a PSU, Hard drive etc.
2) Power - You need something low power. The highest the wattage on Pico PSUs go is around 160 and even using the native PSU (which has its own downside) tops you out at 180. This may not seem so bad, but 40 or so watts goes to power the LCD display. Assuming you may occasionally want to plug something into a powered USB port, that means you should target a system that uses 100 - 120 watts, plenty for an Atom processor, not much for a Core i/Sandy Bridge Setup.
3) Heat - The hardest obstacle has been cooling. Would you ever pick a thick steel cage with a few small holes punched in the top as a computer case? As a convection cooled system, this worked (barely). To air cool requires minimal heat production and a heat sink/fan as close to the air vent/holes as possible.
The core i5 (KEEX-6100) ECX board was the only way I found to solve these problems and it does so very well. It fits easily in the area designed for the 3.5" HDD, its mobile chipset and processor generate less heat and require less power than their desktop counterparts. In fact, I waited around 8 months for the release of this board. I saw the potential when I came across a core 2 Duo ECX board (KEEX - 4030), but the onboard graphics were not OS X compatible.
Its a specialty, almost custom board, so it is overpriced, no doubt, but no good core i5 setup is going to be particularly cheap. You could try one of the other ECX boards (i.e. core 2 duos or atom boards), or a nano/pico itx board, however, these may not be hackintosh compatible, the KEEX-6100 definitely is. It has some great features like a q67 chipset, a compact flash slot (that can be used as a HDD), and a 4 pin connector for power, so a full atx psu is not even needed. If you want a Sandy Bridge all in one in an iMac G4 shell, I highly recommend using this board.
There is no adapter available, apple never intended this LCD to be used with anything else. Keep in mind, its not just a video signal, you have to power the LCD as well as the backlights. In terms of converting the iMac G4's video cable to DVI, luckily this panel is TMDS, which is the basis for DVI/HDMI connections. I have an extensive tutorial on my blog as well as a video tutorial on youtube which details how to convert the signal using an inexpensive DVI connector (this is HIGHLY recommended, splicing a DVI or HDMI cable is considerably more difficult and less efficient). This includes both types of 17" iMac G4's necks (there are 2 different necks that use different colored wires). I have a slightly less detailed tutorial on the 20" and the pinout for the 15", but the concept is exactly the same.
17" Tutorial:
http://www.dremeljunkie.com/2011/08/gui ... ds-to.html
Video Tutorial 17":
http://www.dremeljunkie.com/2012/03/17- ... orial.html
20" All-in-One Tutorial:
http://www.dremeljunkie.com/2011/11/all ... ds-to.html
Keep in mind, there is an alternative, no one said you had to make an all-in-one. While I love the all-in-one mod, it is not my most frequently used iMac G4 mod. My main Mac setup uses a 20" iMac G4 and a 20" iMac G5 which have been converted to external monitors. They are hooked up to a New generation mac mini mounted under the desk.
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completedGen1G5.jpg
Originally I used on old iMac G5, but then changed to an iSight when a friend told me the camera's connector is actually a USB connector.
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Simply attach the Female DVI connector and AC power plug to the rear panel and you have an external monitor. To make the dome useful I added an internal DVD burner with an SATA to USB adapter to give the mac mini the optical drive it lacked. While this may not be as "sexy" as an all-in-one, it is cheaper, allows you to build the computer you want to build without the restrictions listed above, and is much more "future-proof". Also, lets face it, while portability is nice, the iMac G4 is a desktop computer, the 20" in particular weighs over 40lbs, its unlikely you'll be moving it around very often.
Just to comment on the monitor/LCD issue. The above mod actually used a slightly different technique using some parts from a 20" Aluminum Apple Cinema Display. I ended up switching to that LCD panel as it is slightly better (the iMac G4, G5, and ACD, are all interchangeable TMDS panels). However, to keep the original look and feel of the original, it doesn't get much better than the native display. It really isn't a bad display and when looking solely at resolution, 1680x1050 on a 20" screen is better than you see today. But thats where the problem is, as its cheaper to make 16:9 (1600x900) 20" lcds than the iMac and Cinema Display's 20" 16:10 format. The 20" 16:10 size panel has pretty much gone extinct and 17" 16:10, while around are not as common as 16:9. Using a different size or aspect ratio will not allow you to use the same monitor housing. Of course many monitors can be mounted on the neck. Even with the components in the monitor housing, the LED monitors today allow for thinner and lighter monitors. Even larger sizes can be used as long as the weight and proportion is similar to the original. You can see this post for some different iMac G4 mods including different monitors/LCDs:
http://www.dremeljunkie.com/2011/02/sum ... -mods.html
Sorry for the long post, but I hope this helps, JB (Dremel Junkie Blog)
