Atx power?

Posted by: Toyj

Atx power? - 03/30/05 07:42 PM

i have a brand new ATX powere supply with a blow hole fan it lookes real nice with the gold fan plates. I was wondering since i was gonna do this clear side mod. Could i use the ATX power supply in the mac or would it fry it? if u need the power scematic let me know.
Posted by: maestro

Re:Atx power? - 03/30/05 08:32 PM

It can be used as long as you have the schematic for the logic board you are going to use. Just
connect the voltages that are needed. What Mac are you going to use?
Posted by: Toyj

Re:Atx power? - 03/31/05 05:26 PM

im gonna use my B&W G3
Posted by: maestro

Re:Atx power? - 03/31/05 06:12 PM

Okay, now you just need to match the voltages using the schematics. Good luck.
Posted by: ubergeek89

Re:Atx power? - 03/31/05 06:53 PM

If I recall the B&W g3's stock pwer supply is nothing more than a 220 watt atx psu anyway, so you should be set.

Posted by: maestro

Re:Atx power? - 03/31/05 07:33 PM

I think you are recalling the beige G3 ubergeek. As far as I know the B/W is all Apple. I would
be happy to check mine though.
Posted by: ubergeek89

Re:Atx power? - 03/31/05 08:22 PM

It is a B&W, however it is rev a and may be different.
Posted by: maestro

Re:Atx power? - 03/31/05 09:49 PM

I have a rev. a (1), you need to learn about what you are saying about computer.
Posted by: whitlock

Re:Atx power? - 03/31/05 10:07 PM

Watch the tone.
Posted by: Toyj

Re:Atx power? - 03/31/05 10:13 PM

thanks for the help but to be honest with u i have no experiance with powersupplys.... so i have no idea wut to do to make it work....
Posted by: whitlock

Re:Atx power? - 03/31/05 10:49 PM

All you need to do is buy a standard ATX power supply and snip the -5v wire from it. Not too difficult. If you are paranoid, just get an ATX cord extender and snip the -5v from it so you won't damage the original P/S.

-5v should be the white one, but doublecheck on the cords markings, and a multimeter if you have one
Posted by: maestro

Re:Atx power? - 03/31/05 11:38 PM

ubergeek, I have been asked to apologize. I am doing that now. Remembber that the
information that we give must be good. If you are not sure, say so, and let the poster know
that you will find the information they need. That is what we do. We give good, solid info,
to help others. Tone be tone, someone must stand up for what is right for this high quatlity
Posted by: maestro

Re:Atx power? - 03/31/05 11:40 PM

ahh, whitlock is the tech to give the info thats needed. use it. its good, and i trust him.
Posted by: soward

Re:Atx power? - 04/01/05 09:53 AM

yes, whitlock is correct. I have done this at least twice myself. I probably have some photos sommewhere, but I think I found some online before my first try.

Now if anyone has the pinouts for a Quicksilver PS, I'd be interested in that!
Posted by: Toyj

Re:Atx power? - 04/01/05 04:30 PM

so all i have to do is snip the white wire and it should work.
Posted by: ubergeek89

Re:Atx power? - 04/01/05 08:13 PM

Sorry for the incorrect info. I'm a 15 year old geek trying to break into the IT field, and I only do modding on the side and I do what I can. If I'm wrong, I'm wrong and lets just move on.
Posted by: Waragainstsleep

Re:Atx power? - 04/02/05 12:55 PM

Here are the Pinouts for most of the G4 PSUs:

Anything newer than a Blue & White is slightly trickier to convert from ATX, though the Yikes/Sawtooth is still fairly simple (Got this to work once). The GigE needs an extra 28V from somewhere which an ATX doesn't have. There are instructions on the site for this though.
Posted by: soward

Re:Atx power? - 04/02/05 01:42 PM

thanx, good link, has what I need. the P4 connector is still a mystery, but I'm just trying to dump more current onto the 3.3v section to see if I can power up a Radeon 9700 (appple OEM) in a Quicksilver.

The small package on a B&W which contains the power and reset/nmi switches appears to output ~28v from a standard molex input -- I wonder if that could be used to drive the 28v on a digitalaudio and up MB? I'd wonder if it could generate enough current for the ADC, but other than that...
Posted by: Waragainstsleep

Re:Atx power? - 04/02/05 02:38 PM

Is the P4 connector an ATX2? I think they're 24 pin. Shouldn't be too hard to find the pinouts for those.

As for the -28V from the B&W front panel, sounds interesting. Are you sure about that? I think the front panels on the Sawtooth are pretty much the same as those. I guess the 28V just switches on the PSU in the older towers and then they moved it to the PSU to cover the ADC connectors which were first shipped on cards with the GigE.

Where is the output for the 28 from the front panel? Don't have one handy to look at...

Post edited by: Waragainstsleep, at: 2005/04/02 15:51
Posted by: soward

Re:Atx power? - 04/03/05 12:15 PM

I'll have to put the meter back on one to be sure, perhaps it was 18v, it runs out through a two pin jumper back to the MB, and the over to the firewire adapter it looks like.

The P4 is a 4 pin connector from the Quicksilver PS to the MB, looks like it suppies 12v (x2) and at least one set provides extra power to the cpu board.

Anyone know which of the 3.3v lines services the AGP bus? smile
Posted by: soward

Re:Atx power? - 04/03/05 09:33 PM

Just checked the output of a B&W's 'front panel' component. While running and tapping just at the connector's interface to the MB one B&W showed 23.1v. That's probably enought to start up a Gigabit/quicksilver class MB.I have no idea what sort of current it can produce, but I'd question if it would run an ADC monitor.

Many ATX PSes have a 4 pin connector dumping 12v which looks like it would fit the P4 connector on these MBs as well.

Some newer ATX PSes even have a 24pin connector which would fit the socket, though some tedious rewiring would need to be done.
Posted by: Waragainstsleep

Re:Atx power? - 04/04/05 01:38 PM

Interesting. Very interesting.....

Nice one.
Posted by: smuth

Re:Atx power? - 07/09/05 07:00 PM

You will need to change 4 wires If memory serves, the schematic is at You can use an ATX on a B&W and a 100 MHZ G4 but not the 133 MHZ machines, they need more power.
Posted by: mordaskyt

Re:Atx power? - 07/09/05 07:29 PM

I am researching the B&W power specs for my own project. The front panel does indeed output 24v. Its to power the firewire bus. However this board is only rated at 15 watts, the smallest 15" ADC panel draws 50, So it may allow the Gigabit/Digital Audio boards to power up but will not be safe to power an entire display. has detailed guides to converting ATX power supplies to run many G3 & G4 systems Here is the B&W guide:

Post edited by: mordaskyt, at: 2005/07/09 19:39
Posted by: Waragainstsleep

Re:Atx power? - 07/10/05 07:31 AM

Post edited by: waragainstsleep, at: 2005/07/10 07:33