Mod G4 iMac with Intel Mac mini innards?

Hi all,

first post, and it's a biggie..
I have a 20" Luxo/iLamp G4 iMac that I love to pieces, far and away the most beautiful thing I've ever owned, and I've given her everything she's ever wanted, 1.5Gb of RAM, 2x300 Gb HDDs, 16XDL DVD+-RW, the works. However, compressing video is a horrible chore, Civ IV is a no-go, and my little Sony S1 Windoze laptop humiliates Luxo in every operation.

The Daystar 1.92Ghz G4 looks like the only option for me, but for what will end up costing over $600 I'll get about 20-40% more CPU grunt, not much of a return.

I've been inside her many times, and it strikes me that the Mac Mini motherboard would fit comfortably in the case, and I've been looking lustily at Meromini Macs that a few folks have put together.
The trouble is, despite getting the service manuals etc, I'm at a loss as to how I can get my iMac's gorgeous screen to take a VGA/DVI input. The power issue I could get around.

Any ideas? Anyone know of anyone who's tried anything similar?

Like any proud Dad would..

Internal spec:

Airport and Bluetooth
Dimm 0 (J22) 512Mb PC2700 RAM
Dimm 1 (J20) 1024Mb PC2700 RAM (both from Crucial.com)
300Gb Maxtor ATA133 6L300R0
300Gb Maxtor OneTouch II FW (incidentally, the exact same disk!)
Pioneer DVR-109, pre-flashed I think (from xlr8yourmac.com shop)

On all occassions, I had no trouble selling on the removed Apple-shipped parts to either PC or Mac owners.
Yeah, I'm pysched by the idea, I've gone in on 4 seperate occassions (2xHDD replacement, 1xinternal DIMM, 1xSuperdrive).

I bought a Pioneer DVR-109, which in Panther needed Patchburn3 to work with iApps, but since I moved to Tiger, I haven't bothered, and I burn in Toast all the time. That said, I haven't installed iLife again yet.

Yeah, I'm going to try and pick up a broken/sick 15" Luxo to play with first, at least until I figure out the display connector and psu issues. Then into my 20"er..

Xlr8yourmac.com are US-based, and ship to Europe, but their shop partner is called Other World Computing on http://eshop.macsales.com, and they sell guaranteed-to-work drives for any given computer. That said, there's no reason why you shouldn't just buy a Pioneer DVR-109 from newegg or similar, as I've taken the risk out of it by using one successfully. The only tricky part is the removal of the bezel, otherwise the xlr8yourmac G4 take-apart is pretty accurate.

Beware though, after multiple openings of the case, I ran the thread on one of the sprung-screws holding the aluminium base shielding on, and I had to drill it out!

Google will have to get me through this one I think..

I'm going to try and pick up an iMac G4 with a working screen and fried board, hopefully the 21-pin connector will prove to be a re-worked VGA lead (it's reasonable to assume, it uses standard Nvidia gfx chipsets and the external connector is VGA). Even a funky ADC lead would not be an insurmountable problem.

Is anyone out there half-way qualified to help with this? I did most of an electronic engineering degree before switching to computer science, but it's been 7 years since I soldered at work.

Anyone want to donate/sell very cheaply a fried iMac? Or even just the display?

If I do figure it all out, I'll take loads of pictures and write up a full how-to. Any help much appreciated!

Updates:
The TDMS cable referred to in the Apple docs defintitely a digital signal cable, which means it's some sort of DVI connector (or ADC, which is essentially DVI).
ADC pinout: http://www.interfacebus.com/Apple_Video_Bus_PinOut.html
Display connectors: http://www.devhardware.com/forums/computer-monitors-79/the-ultimate-video-connector-guide-98686.html

Interesting idea alright.. I know the arm in the 20" one is way stronger, and the base is heavier to account for the extra weight of the 20" screen, so if you did get the 20" screen attached, you'd have to add 'balast' to your base to stop it falling over!
Also, the Geforce 2MXs in the first and second revisions (700/800Mhz) are only capable of outputting 1024x768 even to external monitors.
http://developer.apple.com/document...2_Architecture/iVideo_Display_Subsystem_.html
Which would look yuck on a 20" widescreen monitor..

Sounds like a bit of a downer on that one really.
I've been reading a fair bit about the ICs that drive the 20", which are on the logic board and not in the monitor and it looks like if I do get it working, it'll only be at the native resolution, which probably means no games :-(

Yeah, I actually bought a CD from EBay with all of those service manuals for every Mac 'puter ever made (with free updates, but naturally, I lost the ftp details), including my 20".

Unfortunately, the only teach a repair monkey how to *replace* parts, not fix/mod them, so beyond describing them as a TDMS connector and power inverter respectively, it's not very educational..

I think 'black-box'ing another corpse is the only way I'm going to get the info I need :-(

Not really, the building of an interface between a DVI output and the quirky internal arrangement of my iMac has defeated me thus far. That, and the arrival of C2D 24" iMacs didn't help, I'm close to buying one..
If I could pick up a cheap Mini solo, and a dead iMac (even 15"), I'd get going, but for now, my iLamp is frustrating me with it's lack of oomph (4.5 hours to rip a DVD to FFMpeg in Handbrake). I may just make it a secondary PC when the new baby arrives :-(