December 9, 2007

Power Supply Fun Part 2




After trying to revive a G4 mirror drive door power-supply by replacing the fuse instead of using a screw driver did not help ether. Same sparks and smoke as last time, just the fuse blew instead of continuing to give off sparks as in my first attempt. So on to plan B... After doing a good deal of research online, there was little evidence that you could take a regular atx power-supply and replace a dead G4 MDD PS with it. After removing the pins from the ATX PS molex connector (thanks Matt) and cutting the entire wire from the MDD PS i just had to put the two together. Please note that you need the original molex connector from the old power supply for this to work, or one that fits, a regular ATX power supply does not have the right number of pins.

If you look online the MDD PS has 24 pins and the ATX PS has 20-24 (mine had 20+4). This is not so bad but the wires in each are a little different, so in all cases some rewiring needs to be done. First thing was to figure out what wires I had and what needed to be modified. ATX and MDD are good places to start. for the pin-outs. My main problem where the two extra white(-10v and +25v) and the gray(PWR-OK) wires. The -10v cant be used so ignore it, and the PWR-OK is also not needed. So the only problem was the +25v used for the video card to drive apple displays. Well you could find some way to add 25v to it, but my friend and I figured that it should be fine with out it, which turns out to be correct. However because of this do not try to use an apple cinema display with this tower!

Connect all of these together matching the same colors together, ignoring the white and gray from the ATX PS. Plug it in and behold the computer turns on. I also connected the MDD power leads as well, because they where longer and the ATX PS did not have enough connector to match the two optical drives and the 4 hard disks. Plus a little wire wrap to make it look less messy and protect the wire splices. The final step was to mount the PS in a good place. Because the original was slim it fit in the pack wall, not so much in this case. The best solution I found was against the side where the white speaker box was. I drilled two holes and zip tied it against the roof of the case. If I had more tools at my disposal I would have found a way to bolt it to the top, which would look a little better.

There you have it, a dead MDD brought back to life. It also has more power now, 400w from the 360w of the original power supply.

Update: After several months the G4 is still cranking away 24/7 as my web development server, and apparently this post has come in handy for some one at http://atxg4.com/forum/read.php?3,8

7 comments:

crabby ian said...

Thank you, for posting this. There's very little information out there on MDD to ATX conversions, so your write-up has been invaluable.
I've started writing up my own conversion on Applefritter, but owe you all the credit for doing the hard work first...and for figuring out where to fit the power supply. ;)

Jonny5 said...

Many thanks, this is informative and helpful. As Crabby stated- you did a great service to us MDD owners who just refuse to go Intel !
My G4 MDD will live again...hooray!
Great work and I'll gladly click your links and repay your contribution.

Efeion said...

I am always glad to hear that my projects end up being useful to others, and thank you for the kind responses!

sonyk said...

Thanku for info iwas looking for the same info What was wattaage of the atx power supply and which is the best model fitting into atx case
regrds
kurien

Jeffrey said...

Thank you Efeion! Between your post & Ian's, our G4 is up and running again!

Aldo Bertuletti said...

thanks a lot !!!!
Also in italy everything is going on good with your informations!!!
Have a nice day friend!
bye..bye
Aldo.

Aldo Bertuletti said...

thanks a lot !!!!
Also in italy everything is going on good with your informations!!!
Have a nice day friend!
bye..bye
Aldo.