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g3 b/w dead from atx power supply?

A

andrew34kay

macrumors newbie
Original poster
Dec 30, 2004
12
0
Hi

here are my specs:
g3 b/w powermac
g3 400mhz cpu
pc133 256 mb ram
factory scsi hdd and factory cdrom

by the way for any of those wondering, this is a different powermac than the othre one that i posted about the ram issue.

ok here is my situation. My g3 would not turn on at all no leds, no noise, nothing. so i stupidly tried an atx psu which was unaltered. it turned on but no post, so i went back to the mac psu. worked fine. but after that a couplr of days later, the g3 turns on but no post, no chimes, or visual anything. the 3 leds light up. then a second later the led by the cpu turns off. I have tryed reseting the pram but it doesnt even post so... my question is did i kill it or whatever with the atx power supply move? i know now that im supposed to cut a wire or ground or somrthing like that. thanks for all ur replies. all of ur ideas are welcome, im totally stuck! lol thanks

-ANDREW
 
may be damaged, but...

It's possible you did some damage by using the ATX PS, but if it worked for a few days, you might be OK. Have you tried unplugging the power cord, pressing the CUDA reset button once (near the battery on the logic board), waiting 15 seconds, then reconnecting the power cord? Sometimes power-on issues are resolved by this. You could also have a bad logic board or power supply.
 
no luck, well i guess the logic board is dead then, but what about the cpu and ram that stuff should be unaffected right? thanks for all your replies.

-ANDREW
 
to use an ATX power supply you have to cut the white lead on the connecter, otherwise you may damage your equipment...... :eek:
 
Try pulling the white lead on the ATX PSU and see if it powers up with it that way. It sounds like it is doing exactly th same thing mine was doing when the PSU died. I just modded an ATX and put it in there, and I'm typing from my B&W right now.

Daniel
 
Hopefully this helps you figure out the problem.

you mention that DS9 (led by cpu) turns on and goes out. That means that the cpu is accessing the data bus so thats good. Does any of the other LEDs go off?

Better yet, is the hdd activity light blinking at all?
 
dsharits said:
Try pulling the white lead on the ATX PSU and see if it powers up with it that way. It sounds like it is doing exactly th same thing mine was doing when the PSU died. I just modded an ATX and put it in there, and I'm typing from my B&W right now.

Daniel
Click to expand...

beat you to it
 
well all the leds do light up and only the cpu led turns off, the others stay on, so maybe the logic board is not dead? well i have yet to try th modded atx psu so i will let u guys know sometime tomorrow. thanks for ur quick responses.

-ANDREW
 
The CPU LED is normally off, only blinks seldomly when its requesting the bus. If it stays solid, then the system has probably hung. - Thats what the Apple Service Source Manual says for the Blue and White.
 
Like I said, that is exactly what mine was doing before I replaced the PSU. I would be willing to bet that the logic board is fine and that the PSU is dead.

Daniel
 
well i got an atx psu adn cut the white wire and nothing happened, but i have not tryed messin wtihe batter and the reset stuff. can you guys tell me about that stuff, like if i need to reset anything what? all ideas are appreciated! i will mess with it some more and thanks for all your quick responses.

-Andrew
 
sorry about the typo, it was supposed to say: ... I have not tried messing with the battery and reset the pram... sorry about that. :)
 
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