I think my PowerMac G4's PSU died, what should I replace it with in 2021?

[BronzeLight]

Hello, this is my first post. I have used these forums for reference many times and some of the pages here are very helpful!

I have a problem with a Digital Audio PowerMac G4 that I recently acquired. From other threads I've looked at it sounds like my power supply died.

Symptoms and other notes:

When I press the power button, it lights up for as long as I am pressing it and a red light on the motherboard turns on for a fraction of a second.

The fans do not spin up, no chime/bong, cd drive won't eject, or any other signs of life.

I have reset the pram PMU and I replaced the pram clock battery.

My serial number brings up this on everymac.com: https://everymac.com/systems/apple/powermac_g4/specs/powermac_g4_466.html

What should I replace the power supply with? I'm looking for something affordable. What options do I have in 2021?

On another note I have a working B&W G3 PSU but the numbers are different. I have included a picture with the specs of both, perhaps it could be useful.


Thanks –BronzeLight

 

[AphoticD]

The G3 PSU looks like a pretty good match. Are the connectors to the logic board quite different? If so you would need some pinout diagrams of both units to rebuild the plug to suit the DA.

 

[BronzeLight]

Hmm, I will have to check them as I'm away from the house atm. I suspect the connector might be the same since they are close in years. I should have mentioned that the G3 PSU is currently in a working B&W I have, but I need to access some files on the G4 so a temporary swap would be advantageous if they do end up being compatible.

 

[BronzeLight]

Ok, I checked out the PSUs last night and found the the G3 has 20 pins and the G4 has 22 pins, here is a pic:

 

[Macbookprodude]

Ebay might have a replacement, or you can check out Used Macs.

 

[Certificate of Excellence]

I’d pick up a brand new ATX psu and use one of these converter harnesses.

Apple PowerMac G4 Gigabit / Digital Audio ATX Power Supply Adapter Cable | eBay

If you have an ADC monitor, you will need to use an external ADC to DVI powered adapter. You will receive the power adapter cable shown. In the box.

www.ebay.com

 

[Certificate of Excellence]

Sean @ Action Retro used a MDD harness with a new ATX psu in one of his newest rebuild vids. Worked like a charm - very elegant solution.

 

[BronzeLight]

I’d pick up a brand new ATX psu and use one of these converter harnesses.

Apple PowerMac G4 Gigabit / Digital Audio ATX Power Supply Adapter Cable | eBay

If you have an ADC monitor, you will need to use an external ADC to DVI powered adapter. You will receive the power adapter cable shown. In the box.

www.ebay.com

Thanks for this! If I go this route, do you know if there is anything else I need to look out for other than size/molex cables when shopping for a replacement atx unit?

 

[eyoungren]

Thanks for this! If I go this route, do you know if there is anything else I need to look out for other than size/molex cables when shopping for a replacement atx unit?

You'll need to decide if you're going to run the system with the PSU on the outside and the door down OR find an ATX PSU that is going to fit into that space.

You may have to do some cutting.

This may give you some idea of what is involved.

 

[salamanderjuice]

I second getting a harness and using a new small form factor power supply like Action Retro used in this video.

 

[ervus]

I'd suggest trying a PMU reset. The power supply may be fine...

 

[BronzeLight]

I'd suggest trying a PMU reset. The power supply may be fine...

I actually did do a PMU reset, but mislabeled as PRAM reset it my main post, I'll now edit it for clarity.

 

[BronzeLight]

Seems like one of these adapter cables is the way to go. Thanks for the comments everyone, they are very helpful! If I manage to get this rig going I'll post an update in this thread.

 

[ervus]

It has a CPU installed, right? You could try re-seating the CPU/connector.

If you still suspect a power supply, you could jumper it 'on' and check voltages with a meter. Also, the switch on the power supply is properly set for 110 or 220v?

 

[BronzeLight]

It has a CPU installed, right? You could try re-seating the CPU/connector.

It appears to have a CPU installed, I guess could try to re-seat it.

If you still suspect a power supply, you could jumper it 'on' and check voltages with a meter. Also, the switch on the power supply is properly set for 110 or 220v?

It is set to 115v and I know the outlet works because I just used a Dell on it an hour ago. My dad has a meter I could borrow so I think I'll be able to check the voltages later.

 

[ervus]

That looks like a dual 533 CPU. Those are nice computers. So you pressed the button in the lower right part of your picture?

 

[BronzeLight]

Yes I pressed that button. That's pretty interesting that it might be a dual 533 as the sticker on the back indicates it was supposed to have a 466. I noticed that the ram was mixed so maybe somebody swapped it the CPU aswell.

 

[Certificate of Excellence]

Yes I pressed that button. That's pretty interesting that it might be a dual 533 as the sticker on the back indicates it was supposed to have a 466. I noticed that the ram was mixed so maybe somebody swapped it the CPU aswell.

Entirely possible as my single 733mhz quicksilver is upgraded to dual 1ghz w/ L3 cache. Lots of us tinkerers around.

 

[BronzeLight]

Update: The machine is up and going and the previous owners data has been recovered!
(upon their request of course)

A hearty thanks to: ervus, AphoticD, Certificate of Excellence, eyoungren, salamanderjuice, and Macbookprodude! Your replies proved very helpful!

I ended up purchasing the adapter that Certificate of Excellence highlighted since I didn't have some of the required parts in my stash. The machine is a 533 MHz G4 with 1gb total ram over 3 sticks (2x 256 and one 512) running OSX 10.3.9. Another quirk about this machine is that it has a Zip drive but it's missing the cutout for it on the front bezel! Everymac says Apple did sell some models with Zip drives but this one is held in with only one screw... my gut still says "factory" but maybe it was added in later!

My plan for this machine is to do a nice deep cleaning and pick up a more permanent PSU. Thanks again!

 

[ervus]

Thank you for posting a follow-up; I'm glad you got it going!

 

[BronzeLight]

I intend to post another update when it's cleaned up all nice and shiny