Power Mac G4 Digital Audio randomly shuts down, won’t boot with PCI cards installed

[ShortFormErnie]

Hi there,

I’ve been working with a Power Mac G4 Digital Audio (533 MHz) off and on for about a year trying to get it working again; it’s kind of a light hobbyist machine for me to see if I can get it working.

Anyway, I’ve had trouble getting it working because of reasons I believe may be related to the power supply. The machine for some reason will not boot if I add an expansion card like a SATA or USB 2.0 card. The light comes on with a card in but the keyboard remains unresponsive and the screen does not display. While I can get it to boot with a hard drive (though the HDD itself gave me issues, long story), I have found that after finally getting Tiger installed, the machine has a tendency to shut down at random intervals. When installing Tiger, in fact, the machine randomly shut off twice.

At the moment, the machine has a maximum 1.5 GB of RAM, an ATI Rage 128 with DVI in the AGP slot, and a 120 GB 3.5 IDE hard drive. The RAM is fully detected and the battery is new and has been reset.

My guess is that this is the power supply to blame, but I figure that the experts may have a better idea. Could it be something like the power strip, or possibly something poorly seated? I wanted to know if anyone had any suggestions here for getting the power supply back to proper function or any other suggestions I might be missing.

 

[Raging Dufus]

It could be the power supply, but I think the problem is likely somewhere else. Other things are easier to correct. First things to try:

1. Re-seat the graphics card.
2. Re-seat the CPU daughter card.
3. Re-seat the RAM.
4. Replace the PRAM battery, and don't forget to press the CUDA Reset button on the logic board afterward. On yours, the button might be labeled PMU Reset, I'm not that familiar with the Digital Audio.

You mentioned your DA has a Rage 128 with DVI. This tells me there's been some swapping around going on with your machine, because DA/533's came with the GeForce2 MX. So either yours was once a DA/466 and the CPU's been swapped, or it's always been a 533 and the graphics card was swapped. Also, the Rage 128 that came with the DA/466 had ADC + VGA outputs, not DVI. So it's likely your graphics card came from a Sawtooth, which did have DVI. In any event, something on your Power Mac is not original equipment. It's a reasonable assumption that the problem may lie in some of the replacements, so try:

• Swapping out the CPU daughtercard, if you have or can get another one. Doesn't have to be back to a 466, you should be able to use any single-CPU daughtercard from a Digital Audio or Quicksilver, from 466 up to 933 MHz. *EDIT*: I'll have to take that back. An electrical modification would be needed for your DA to run a QS processor. Search around the forum for more info on that, but if you're not willing to mess with it then stick to known Digital Audio CPU's.
• Swapping out the graphics card, if you have or can get another one. Doesn't have to be a GeForce2, and doesn't have to have ADC. Just check online for compatibility with your Mac's 4x AGP slot. A number of cards will work, though some may require modifications. Search around the forum here, there's lots of info on that.

IIRC, the AGP graphics slot in these old Power Macs ran with the PCI expansion slots, on the PCI bus. If I'm remembering that right, it makes sense that a problem with the graphics card would have effects on the PCI slots as well. So, my money's on a graphics card issue. Hope this helps. Good luck!

 

[ShortFormErnie]

You mentioned your DA has a Rage 128 with DVI. This tells me there's been some swapping around going on with your machine, because DA/533's came with the GeForce2 MX. So either yours was once a DA/466 and the CPU's been swapped, or it's always been a 533 and the graphics card was swapped. Also, the Rage 128 that came with the DA/466 had ADC + VGA outputs, not DVI. So it's likely your graphics card came from a Sawtooth, which did have DVI. In any event, something on your Power Mac is not original equipment. It's a reasonable assumption that the problem may lie in some of the replacements, so try …

Thanks for the response! This is correct; fortunately I was doing the swapping. I switched the video card myself because I don’t have ADC-compatible monitor. I could try swapping back in that original card, which I believe has a VGA port. I have a VGA-to-HDMI adapter which will work in a pinch here.

I will try the other things you suggested. Also, regarding the daughtercard, I’m assuming it’s never been repasted, so I likely will do that as well. Will give this a shot, thanks!