Here's another problem.
I recently bought a 1 GHz DP QuickSilver for cheap because the seller couldn't get it running. I'm fine with the expenditure because the parts (CPU, video card, superdrive) are worth more than I paid. Still, I'd like to get it running...
I've got a 933 MHz QS G4 CPU that I know works, and I dropped it into the QS for a test. Otherwise, the system is completely empty - no RAM, no drives, no AirPort card, no PCI cards, no AGP card, no USB devices, no FireWire devices, no modem, no nothing. All that's connected to the motherboard is the speaker, front panel board, power supply, 933 MHz CPU, and CPU fan. I have tried this with and without a PRAM battery, as well. Pushing the power button causes this: The power LED comes on very briefly and then goes out. The PSU and case fan spin up briefly, then they shut off on their own. That's it. There's no chime and no diagnostic tone.
So at first I figured it was a faulty PSU. But I don't have another PSU available that I can rewire to a QuickSilver configuration (closest I've got is an MDD PSU wired up for a DA G4 board and missing the extra ~28 V on pin 9). Instead, I tried a DA G4 board w/ G4/466 in the QuickSilver case (after disconnecting pin 9 from the PSU, of course). Starting up from there results in a slightly different set of symptoms. The power LED comes on as long as I'm holding the button, but fades after I let go. The PSU stays powered in this case, but the motherboard doesn't do anything interesting except light up the red LED next to the RAM banks.
Any ideas on this one? Could it still be a bad PSU?
Does the QuickSilver really need a special 28 V line on pin 9, or can I just tap the 28 V trickle on pin 22 for pin 9 as well? If so, I could test this with the MDD PSU. I really don't want to go buy another PSU that I don't need, especially since QS PSUs seem to be fairly expensive.
I have found that the G4s NEED something on the 28v line but not all 28v. On my Gigabit, 12v allowed the board to poweron and boot up, otherwise it wouldn't do anything.
Thanks for the tip. I'm not talking about the 28 V line that every ADC equipped Mac has (or maybe I am but don't know it - that's the problem). Most ADC Macs only have one 28 V line on the PSU, but the QuickSilver has _two_. One is marked as "trickle," and that's the one I've assumed supplies the 28 V line for ADC. The other is not so marked, so that's what I'm confused about. Is this 2nd 28 V line (found 3 or 4 pins down the in on the connector on the side with the latch) also used for ADC and thus not actually required?
I'd try throwing 12v on there and see what happens. Not much can happen from being under voltage.
Amongst all the details you've reported, I failed to notice if you've tried the QS MLB/CPU in your DA?
You can run any G4 PM off an MDD supply with the proper wiring mods (or custom interfacing wiring adapter), you sure your MDD PSU actually works? Where's your VOM in all of this, have you actually checked for proper voltages?
Really, the only sure way to test stuff like this is to have a complete working example of each and every Macintosh model. Just explain to your fiancé (wife?) this fact, she's sure to understand the need to have ~53 Macs around the house.
PS: heh, sure looks like a bum PSU to me though . . .
...or didn't you try to push the pmu reset button??? just at the very moment i had an older G4 in the office, same symptom, after pushing the button on the front the led would go on for a moment but went off then. i pulled the power plug, pressed the PMU reset button, waited ten seconds, then plugged it in again and - voilá - boot tone and led stays on, os9 fires up!
maybe worth a try, sometimes it can be that simple. but be sure to check the voltage of the pmu battery, should have at least around 3,5 volts...
Yep, it's "wife" now. A happy 1 year and 3 months, even! She's pretty understanding. The only thing she complains about is the number of monitors. But then I remind her that she's got two Apple Studio Displays connected to her B&W G4, and she quiets right down again...
I haven't tried the QS motherboard in the DA (or on my converted MDD PSU) because I was nervous about the extra 28 V. Since everyone seems to think it's not a problem, I'll give it a try tonight or tomorrow if I can...
I haven't pulled out the voltmeter yet, but I may do that soon. I just have to find the free time without having to explain to my wife why paying attention to the Macs is more important than paying attention to her! So far I've been working on the stolen minutes here and there before she wakes up in the AM.
I'm thinking bad PSU as well, but I'm a little confused about it. The DA board shows exactly the same symptoms in my MDD PSU/QS CPU/DA MLB/8600 case conversion project. What are the chances that I've got two good boards and two bad PSUs?! I think that would be a first for me - I've never actually witnessed a PSU go bad. I suppose it's possible the MDD PSU is bad, but I bought it under the belief that it was fully functional. Hmm. It wouldn't be the first time an eBay seller misrepresented his goods, I'm sure...
Thanks for the reply, Chris.
Hmm, no, I haven't tried that on the QS board, actually. But I have tried the QS board both with and without a PRAM battery.
I did a reset on the DA board I tried, but that didn't help. I suspect that if the DA board didn't fire right up, that I've got a bad PSU. What do you think?
sorry for the late reply, but i was having big troubles with that darn g5 of my boss.
you could test that out, there are 2 wires you would have to short out, than the psu should come up and power the fan in the back of it. it should be the green one (well, at least it's the green one for atx power supplies), but don't nail me down on that, i'm not quite sure on this.
Well, I finally got in there with a multimeter while the DA G4 board was plugged in. All the pins read the appropriate voltage. I can't test it with the QS board in because the QS board powers down the power supply after a few seconds, and I don't have enough time to test the pins that way.
Anyway, all the voltages are correct. So it looks like a dead mobo problem.
I dropped the supposedly working DA G4 board into my KNOWN working DA G4 case (replacing a working motherboard), and it displayed the same symptoms as when in the QS case and using the hacked MDD PSU.
So it looks like both the QS and 2nd DA boards are bad. That's a shame because supposedly the Dual 1 GHz board supported large (> 128 GB) hard drives, but at least there seems to be plenty of DA G4 boards around so I'm not totally out of luck.
I agree, I have a G4 Gigabit with a dead psu. I just got it working with a 250 watt AOPEN ATX power suppy that I had lying around. I spliced a few wires so all the voltages and grounds matched up. Then, I used the +5vsb wire from the atx power supply to supply +5v instead of +28v (or +12v as mentioned above). As protocol6v states, the motherboard needs some voltage on the +28v line to power on. The ATX +5vsb is a standby voltage that is always providing power when the psu is plugged in. That way the motherboard has just enough juice to know when you've hit the power button and then it turns the whole computer on.
I believe the only drawback with this method is that the ADC connector probably won't work correctly and any firewire device will nedd to get it's power through an external ac adapter. I don't have an ADC monitor or any firewire devices that are powered through the firewire cable, so this solution is perfect for me.
^ Yes, I can verify the post above.
G4 Digital Audio, with Antec TruePowerTrio for the power supply.
Made an adapter with this guide: http://www.outofspec.com/frankenmac/wire.shtml , fed the +5Vsb to the pin that gets+28V from the original PS, goes to DeepSleep an wakes without any problems.
The added beauty of the mod is, that now the power supply's 12 cm fan is drawing the air past the processor so the cooling is way better then with the original configuration (in the DA and Quicksilver-G4's, the processor is located right next to the PS.
NB: if you want the fan facing the processor, the ps mounting screw holes do not match - I used zip ties through the PS grille to the the strut that divides the openings for the original fan and mains plug.
A quote from my own post to Strangedogs forum: