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View Full Version : Custom Heatpipe to hack an imac G4 with x86 motherboard?




pubjoe
Feb 8, 2011, 10:55 AM
This may be a stupid idea...

There have been many methods discussed about squeezing a modern computer into an imac G4. None have been 'perfect' and compromises have always been made. Space is the biggest problem.

What if the imac's existing cooling system was kept intact? All we would need is to make a custom heatpipe that transfers heat from the new CPU (on a small motherboard) to the heatsink plates on the top part of the dome.

As a rough guide, I've checked the thermal output on this page (http://support.apple.com/kb/HT3468) - a 2.66ghz core2duo system has the same BTU under load and a cooler BTU at idle as a G4 1.25ghz. So I reckon the existing cooling system could handle the new chip.

Making a single part would be quite expensive. Maybe if there was enough interest, several could be produced to save money.

After that, there is the issue of power supply, routing the ports and converting the video signal. All of that has already been done (I think the video conversion only worked with the newer imac G4 models).



Transporteur
Feb 8, 2011, 11:25 AM
You can buy straight heatpipes (don't ask me where, I looked into that about a decade ago ;)). All you'd need then is a pipe bender for small diameters and a CNC for manufacturing a custom heat sink.

That sounds easy, isn't achievable for the majority of individuals, though.
That being said, I'd rather place a small active cooler on the CPU, without fiddling around heatpipes and such. Cheaper and given the TDP of a Core2Duo probably doable.

pubjoe
Feb 8, 2011, 01:07 PM
Thanks. It at least sounds do-able.

The trouble with using a small cooler directly on the CPU is that even if you could fit one in only about an inch of clearance under the optical drive, it would be so cramped that I don't think it would move any air. On top of that, if you could somehow use tiny side-mounted fans to move air horizontally, I don't think the warm air would exit the dome case sufficiently.

...If it could be made to work it would be a lot easier though.

fhall1
Feb 9, 2011, 06:32 AM
The hard part's going to be connecting video off the PC motherboard to the iMac LCD and getting it to work.

pubjoe
Feb 9, 2011, 10:24 AM
I'm pretty sure the newer model imac G4 screens can be adapted to dvi. I'm on my phone right now so it's difficult to look up the information, but I know that this has been a greatly discussed long term problem which someone has recently written a detailed solution and supplied pinout diagrams for. ...Brightness control was sacrificed though.

I'm sorry I'm not giving credit to the person right now.