G4 Power Supply Swap-Adapter Cable Has The Wrong Connector From ATX PS to Adapter Cable
- Thread starter 2112st
- Start date
(sigh)
I guess, for the time being, I'll have to put the old power supply back until I can figure out what to do. It still works, although occasionally, the computer won't boot-then I have to unplug the power cable and plug it back in-then it will boot.
I guess, for the time being, I'll have to put the old power supply back until I can figure out what to do. It still works, although occasionally, the computer won't boot-then I have to unplug the power cable and plug it back in-then it will boot.
If you got a bong, it should be good. What video card are you using, and what type of display? Are you using the DVI port or the ADC port? If using an ADC monitor, I don't think it will not work, as you don't have any 28v power from the PSU.It powered on, but no picture.Edit: I did hear the start-up bong.
Here are the photos. The adapter is DVI to VGA, and then the VGA cable goes to the back of my 32-inch Panasonic Viera TV. Also, another problem-I was able to connect the mechanical HD & SSD to the two power connectors, but there's nothing left to connect to the CD-ROM drive.
It's been a long day-I've spent longer on this project than I expected. I'm still going to put back the old PS for the time being, and then figure out how to deal with these problems later.
Thank you all for your help! Any other suggestions are welcome.
I reassembled the MDD Mac with the old power supply reinstalled. It's in working order again. I plan to hold onto the new power supply., since it seems to work. The question is: why didn't I get a picture? I also need to figure put a way to add power extensions to the CD-ROM drive, since I could only power the boot up mechanical HD (OSX 10.4) and SSD (OS9).
I guess this is my MarchIntosh project, eh?
I guess this is my MarchIntosh project, eh?
It powered on, but no picture.
I had the same issue on a G4 MDD with an ATX power supply swap (I could repair the failing original Samsung PSU in the mean-time and all works properly again, but still like to get to the root of this ATX issue).
With ATX PSU, the machine powered on with the startup chime, but no video on the ATI Radeon 9000 Pro card (connected via DVI to VGA converter to an LCD) and also no further activity from the hard disc (after spin-up).
Voltages measured as they should be. Using a second ATI Radon 9000 Pro not even created the startup chime (both GPUs work properly with an original PSU)
However, with the ATX PSU and using an ATI Rage 128 Pro from a 400 MHz G4, it started with bootup chime, video went on and the hard disc booted properly.
Atm my hunch is, that contrary to what is stated often, (some?) Apple ATI Radon 9000 Pro cards might need the 25V line to initialise properly (and with that continue the boot process)
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Follow up: I used a step-up converter to create 25V ADC would need, but that didn't solve the boot problem with the ATI Radeon 9000 Pro. Unfortunately I only had an oversized EVGA 1300W G2 PSU for this test, so other factors might come into play here (the ATI Radeon doesn't like).
Anyone having a good idea what could go wrong in these cases where the nominal voltages are all there?
Anyone having a good idea what could go wrong in these cases where the nominal voltages are all there?
Three other findings
- isolating the ADC connector of the gpu still lets the G4 bootup (and show video on DVI/VGA of the Radeon 9000 Pro) with the original PSU; so, the card doesn't need 25V to finish its start sequence
- switching to an ATX power supply (tried a second one with 1000W) however only produces the boot chime but no video or further boot sequence
- removing the Radeon 9000 Pro from the machine creates the boot chime and lets the machine boot into the desktop (you can use the keyboard shortcuts and shut it down from there)
Has anyone (that has an oscilloskope) measured how the voltages are ramped up and when e.g. PowerOK signal is enabled (/PowerOn grounded) on the original PSU? It looks to me like the timing of the lines being up could be slighty different with an ATX PSU vs. Apple's PSU, preventing the Radeon 9000 Pro to go properly through its start sequence (and with that stopping the whole boot process).
- isolating the ADC connector of the gpu still lets the G4 bootup (and show video on DVI/VGA of the Radeon 9000 Pro) with the original PSU; so, the card doesn't need 25V to finish its start sequence
- switching to an ATX power supply (tried a second one with 1000W) however only produces the boot chime but no video or further boot sequence
- removing the Radeon 9000 Pro from the machine creates the boot chime and lets the machine boot into the desktop (you can use the keyboard shortcuts and shut it down from there)
Has anyone (that has an oscilloskope) measured how the voltages are ramped up and when e.g. PowerOK signal is enabled (/PowerOn grounded) on the original PSU? It looks to me like the timing of the lines being up could be slighty different with an ATX PSU vs. Apple's PSU, preventing the Radeon 9000 Pro to go properly through its start sequence (and with that stopping the whole boot process).
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