G4 to ATX conversion

Posted by: bombsquad

G4 to ATX conversion - 05/14/08 03:22 AM

I'm building a simple rig for someone that will consist of a G4 in an ATX with LOTS of cooling, and about 9-10 drives. I'm looking at the LIAN LI Armorsuit PC-P60 case for pass thru cooling

This machine works well, but runs hot. The unit is only used for network backups at the present time, but we also want to use it for a NAS device for their archival storage.

1 TB network backup and 6-7 TB for archival storage, plus offsite FireWire backups.

What I'm wondering is, if anyone knew what type of power supply I would need for 9 or so drives on a G4? I'm pulling the logic board from a dual 1ghz quicksilver

If I have to put a bigger power supply in, what do I need to put in? Suggestions?

I have my own G4 to ATX conversion at home with 5 drives, at it stays cool all the time, but this needs more drives.

Rob Frank
Posted by: godicm

Re: G4 to ATX conversion - 05/14/08 10:07 AM

if you had a G4 sawtooth (10 pin logicboard powerconnector), you could have used pretty much any ATX and adjust the pinout.
if you have any other G4, such as your quicksilver, you will need a PSU with one 28V lead. the board will not work without the 28V. this means: forget any ATX PSU.
in this case i might suggest an MDD-PSU. they give 380 or 400 W and are relatively easy to find on ebay due to apples past exchange program for noisy MDDs.
Pinout must be adjusted in any case!
btw: the old quicksiver PSU can be sold on ebay for a good price. there is a high demand as they seem to be the most failing component in quicksilvers....
Posted by: macDeviant

Re: G4 to ATX conversion - 05/14/08 03:55 PM

I've always wondered though. Is the 28V required for start up or just to power an ACD? I know with the G4 Cube it is required for the computer to start up at all.
Posted by: godicm

Re: G4 to ATX conversion - 05/14/08 04:24 PM

yes, the 28V is required for the logicboard to work. (i tried a DA and a QS with 12V instead of 28V - didnt work). maybe there is a hack, but i never found out.
as far as i know, this is valid for all G4 except the sawtooth.
fyi: the G5 models seem to boot nicely with a converted ATX-Powersupply.

shame i can't find that page with all the pinouts again. every model has its own pinout, so watch out.
Posted by: oojacoboo

Re: G4 to ATX conversion - 05/14/08 05:38 PM

You might need to run a second PSUs on the box for all of those drives, im not sure.

Also, another thing to look at with that rig is iSCSI, its pretty sweet for performance.
Posted by: Waragainstsleep

Re: G4 to ATX conversion - 05/14/08 08:31 PM

I have the G4 pinout page, be interested to get them for a G5 though.


I would recommend against going with two separate PSUs. I think you need a decent, high-wattage unit to mod.
I built a smurf back in the day and the HD wasn't recognised when on the built in IDE bus but a separate PSU (from an external enclosure). Last week I encountered the same phenomenon with an MDD and a drive running from a SATA PCI controller.

I have run MDDs with 5 drives in them on the stock PSU with no issues. One was a dual 1.42GHz, the other was a single 1GHz upgraded to dual 1GHz. If you have an older G4, it would seem fair to assume that it will be drawing less juice than either of these. Going by memory, none of the MDD PSUs exceeded 400W by much.

Based on this, I would say a 600W unit would be a pretty safe bet. With this many drives doing a fairly important job, it might be worth forking out for a more expensive, high quality model.

If you want to take the time, you could look up the power consumption of the drives you have your eye on. And I'm sure you can find the consumption of your G4 chip too.
I believe Seagate have recently launched some low power drives too.

Are you using hardware RAID controllers?
Posted by: bombsquad

Re: G4 to ATX conversion - 05/14/08 08:53 PM

Ok, a little disappointed here. Oh well, I was trying to build a raid system that could do what was stated above, but also shut itself down on weekends, and restart on monday(Energy conservation, plus their location gets real hot during summer months especially on weekends when AC systems don't run as much).

I was also trying to centralize all backups and archives into 1 location. I do have some old MDD G4's lying around, I could just build an archive system on that, and keep backups on separate system.

Waragainstsleep, yes, I was planning on using a raid controller from highpoint.

I would consider using a MDD logic board in an ATX box (they got just as hot as Quicksilvers!), but Its kinda hard to fit their logic board into a ATX case when they inverted PCI placement.

Maybe we'll just use external FireWire or eSATA raids. If i was planning to iSCSI, i would have them invest in something like an Xserve, with some sort of storage.

Keep the suggestions coming, I'm still in planning stages.

Posted by: 4JNA

Re: G4 to ATX conversion - 05/15/08 07:57 PM

peecee works for me ;D i'm running a QS 733 overclocked to 933 with a pc ATX supply here. i used the +5vSB for pin 22, +12 for pin 9, changed pin 8 to +3.3, changed pin 19 to GND, and so far no problems. i used an ATX extender and modified the wires in the extender so that any standard ATX supply could be plugged in without worring about wires and such. watch out, on the seperate 4 pin +12v feed connector, it's backwards from the ATX supply (swap yellow and black) at the logic board end. compare with the original supply to double check!

i gather from reading boards that external power firewire devices would not work, and using an ADC monitor would not work. i have neither, so can't comment. i'm using a flashed 9800, 1.5gb ram, sata pci card, and a couple of 500gb drives, and have not had a single problem. best of luck.
Posted by: bombsquad

Re: G4 to ATX conversion - 05/16/08 04:49 PM

4JNA, you've said you've done it successfully, so now I'm interested again!!!!

I'll look at your pin outs again and check. I am concerned about Firewire. We use external Firewire 400/800 drives (OWC Mercury Elite Pros) and rotate them every 2 weeks. I guess you meant bus powered FireWire? And as far as ADC, this unit will be headless, so I wont even need a display.

Also, any particular ATX PSU you selected? Recommend?

Please let me know, gears are a turnin i my mind!!!


Posted by: godicm

Re: G4 to ATX conversion - 05/16/08 04:56 PM

i checked the new info on my frankenstein mac. switching the 28V with 5vsb works!
cool! that gives plenty of possibilities in reanimating dead macs with cheap ATX-supplies. thanx 4JNA!
firewire works too. if its buspower is on or not doesnt matter to me.
Posted by: 4JNA

Re: G4 to ATX conversion - 05/16/08 08:15 PM

Originally Posted By: "bombsquad"
... I guess you meant bus powered FireWire? And as far as ADC, this unit will be headless, so I wont even need a display.

Also, any particular ATX PSU you selected? Recommend?

yeah, long day and coffee was wearing off, i did mean bus powered. sorry for the slip.

was going to try and borrow a powered firewire drive to try, but looks like the post above beat me to it. glad to know it works! i also thought about just adding in a PCI firewire card if i ever needed it.

power supplies; i use a lot of THESE and love them. lots of stable power, really quiet, 80plus means less power is turned into heat, etc.

of course, pictures of your build will be required, but you probably already knew that. best of luck.
Posted by: Lamer980

Re: G4 to ATX conversion - 07/31/08 10:13 AM

I was just thinking of doing the very same thing. With this setup, is it possible to replace the Apple power supply with a stronger quieter one? Or is the power supply proprietary.
Posted by: mikejohn

Re: G4 to ATX conversion - 08/21/08 04:55 PM


A standard PC ATX Power Supply does not have 28V DC and will not be pin compatible with the Gigabit G4 and later G4 systems. I wanted to clearly note the ADC/28V issue for anyone thinking of using a standard PC ATX supply for a conversion with the summer 2000 and later G4 systems. For all but the Mirrored Drive Door G4s (which use a non-standard form factor power supply) - the original Mac Power Supply will fit in most ATX cases, if the cable(s) will reach the motherboard of course just use your original Mac P.S. (You can sometimes find Gigabit/Digital Audio and Quicksilver Power Supplies for sale at Ebay if your PS has failed.)-Mike

If you want more detail so join me wink
Posted by: alsa

Re: G4 to ATX conversion - 09/29/08 10:11 PM

It doesn't need to be bigger, but have more power. So look at different power supplies specs.
I would recommend to look for x5 as more power as the original unit. That wouldn't be easy to find though.
Posted by: edfresh

Re: G4 to ATX conversion - 10/01/08 03:28 PM

Are you talking about the X5 power unit? It is well hard to find! I had a simular problem myself, I found loads of information on the net. I managed to get one in the end from some American site, check out the link it may help you! If not you can always try ebay!


Graphic Design Worthing
Posted by: renet

Re: G4 to ATX conversion - 10/05/08 02:50 PM

I really don't have anything to add to this post. At this point just a spectator learning about macs. So, far only using pc's but have friends that have a mac notebook for each family member and they love them.

It appears the original poster re "G4 to ATX conversion" has received nice informative responses. I am impressed with this forum!
Posted by: TomJaguar

Re: G4 to ATX conversion - 10/22/08 06:58 AM

I've been trying to put a flashed GeForce 3 in my Sawtooth Gigabit G4 but I'm getting the same flickering image problem most people that have tried this have had. The problem is that the card doesn't draw enough power, which is not surprising since the PSU in the G4 is only about 200W. So I'm thinking about replacing the PSU with a new ATX PSU. However, the only conversion scheme I've been able to find is for pre-gigabit sawtooths (the ones that don't have +28V DC required for the ADC connector).
Posted by: Answers4PC

Re: G4 to ATX conversion - 11/30/08 01:14 PM

I am currently learning about Macs also, I have heard they are good machines but looking at this post seems like they are well looked upon. This topic seems to have a number of quality reply to the original problem, Ill be sure to make some topics on this forum if i have any issues with a Mac if i get round to buying one.

Hope your problem is resolved. smile
Posted by: sinirsire

Re: G4 to ATX conversion - 01/17/09 05:15 AM

I am also looking into the G4 mirror door mac conversion for better and more stable power but little confused on the pin outs. There people out there that completed this conversion with minor issues but really wandering if the time for it is worth it. I also finding people have take G5 tower power supplies able do the same wandering what is the best option for me. Would like to do other mod to this machine besides adding power supply.