Hey guys remeber my powermac g3 B&W to g4 mod. well i put it back together to try and get it to boot this weekend and it didn't boot still got the DS5 red light on and no hard drive spinning no video signal no cd rom noise. well i figured out what the problem is and its that the powermac G3 B&W's PSU is inatiquit for powering the G4 board and chip inaddition to the HD and Cd rom/ZIP. So if anyone ot there has a AGP graphics G4 PSU and is willilng to ship it to me for free to keep that would be mighty great casue i'll be able finish my first mod. If no one has a g4 AGP graphics PSU then cab you find the cheapest one on the web for me cause all the ones i'm finding cost 250$ and that is lick over twice what i spend on this mod.

Build your own from a cheap ATX:

http://www.outofspec.com/frankenmac/wire.shtml

i'm don't think i can do that yet. I don't want to risk detroying the board i have and my chip and all the other parts. doesn't some company sell a cable that automatically converts an ATX PSU to a G4 PSU.

Just use a standard ATX extender cable and snip out the grey and white cables. You can then re-connect the grey to one of the orange 3.3V feeds, Its not a massive voltage, so just stuffing it in there firmly should do the job.

As long as you follow the instructions on the above link, you won't fry anything.

Ohh delete this one... thought he was talking about a b&w board.

[censored] getway i got for free. the machine was a pentium 4 1.5ghz. How can i tell if the PSU is an ATX. The motherboard from this pc is smaller than others i've seen so it could be an ATX but i'm not sure. please tell me how to figure out what kind of PSU it is

the PSU i found is 160 watts i don't think it has enough juice to power my g4 board

If it is a 20 pin connector, it is almost certainly ATX. (Same connector as the B&W and AGP boards have on them) Again, check the link above. You'd be surprised how many different PSUs follow the colour conventions shown there. Even the cheapo ones.
ATX2 has either 22 or 24 pins (I forget). If it is smaller than ATX, it could be mini-ITX or something else entirely. I forget roughly when the transition from ATX to ATX2 occurred, I would guess a P4 1.5 could be either one. A P3 or older is almost guaranteed to be ATX unless its a mini-PC or some kind of server.

The G3 psu should be able to power the G4 board. If its an early sawtooth, you should have no problem converting an atx psu. I suggest the Thermaltake 430w. Its cheap and will work fine with what you want. Check out the conversion on xlr8yourmac.com.

i have a question about PSUs. What does it mean when an ATX PSU has a 20+4-Pin connector. Does this mean that it can connect to both a board with a 20 pin port and a 24 pin port.