Power Mac G4 strange experience/stopped working

[higgers]

Hi, i am really hoping someone can help. I have had a bit of an odd experience and wondered if anyone can shed some light. I recently sold a Powermac G4 to someone and it was working (tested and powered on with the sounds but not tested with the screen). I had left it plugged in at home and thought nothing of it. It was last tested and working probably 2 days before collection. Unfortunately, it wasn't tested on collection. I then received a message concerning it not working. I have refunded the buyer and now got the item back, and have been trying all of the online solutions to no avail. It just seems so strange and I can't get my head round it. I have two thoughts, could a thunderstorm/bad weather whilst it being left connected cause an issue? Or two, I don't want to be accusatory, but is there anything that the buyer could have done to the PowerMac, ( would have had to be a quick job as they messaged within lets say 10 minutes of getting home) perhaps stripped/replaced that would stop it working (perhaps a valuable part or something). I've looked at the photos I have of it and I can't see any obvious differences and I dont want to believe that this is the case as the buyer has good feedback. I am actually left a bit shaken as I am an honest seller and the buyer seems quite accusatory claiming that he thinks I knew it wasn't working.
I am not very PowerMac literate as I am sure you can tell. Any help would be much appreciated and any solution to get it working (if possible)
would be amazing! Thanks!

 

[eyoungren]

We're here to help, so exactly what is the problem?

Does it chime and fail to boot, or does it not chime at all? What specific problems are happening?

 

[higgers]

We're here to help, so exactly what is the problem?

Does it chime and fail to boot, or does it not chime at all? What specific problems are happening?

No chime or anything, before it chimed and had light

 

[eyoungren]

So testing…

Pull out all the installed cards and all the ram except for one stick. Somewhere on the board should be a red button. Press that ONCE, no more. Put the graphic card back in and hook it up to a display. Then try and turn the Mac on. See what happens.

 

[TheShortTimer]

Hi, i am really hoping someone can help. I have had a bit of an odd experience and wondered if anyone can shed some light. I recently sold a Powermac G4 to someone and it was working (tested and powered on with the sounds but not tested with the screen). I had left it plugged in at home and thought nothing of it. It was last tested and working probably 2 days before collection. Unfortunately, it wasn't tested on collection. I then received a message concerning it not working. I have refunded the buyer and now got the item back, and have been trying all of the online solutions to no avail. It just seems so strange and I can't get my head round it.

I experienced this with my Power Mac G4. It was working without any issues within a 24 hour period but inexplicably wouldn't power up when I attempted to switch it on a short while later. Just as @eyoungren has advised you, I pressed the CUDA button on the logic board and it eventually sprang back to life after a few hours.

Years later the issue reoccurred but this time the computer never worked again. It's possible that your machine could have met a similar fate but fingers crossed, you'll have better luck than me.

 

[rgwoehr]

Earlier this year, my G4 Digital Audio would stop working if I had it unplugged for more than a couple hours. The first time it did that, I was able to get it to start up again somehow (probably by doing what was mentioned in the post above), but the second time it happened, I got no lights or anything, and when I checked the voltages on the power supply, it was dead. I sent it out and had it rebuilt and it's fine now.

 

[scarlett7447]

No chime or anything, before it chimed and had light

It could be that the power supply has died, as @rgwoehr mentioned with their G4.

 

[Webster's Mac]

Most likely the PSU. If the CUDA reset doesn't work, you are plugged into a known-good outlet, etc. There's a service on eBay (if you are in the US) and they repair these. I have a similar G4 to yours, and the caps were in really bad shape.

REPAIR SERVICE Apple PowerMac G4 Mirror Drive Doors Power Supply MDDOpens in a new window or tab
REPAIR SERVICE Apple PowerMac G4 Quicksilver Power Supply QS API1PC12Opens in a new window or tab
REPAIR SERVICE Apple PowerMac G4 Digital Audio or Gigabit Power Supply API-9841Opens in a new window or tab

 

[Webster's Mac]

You will need to know which PowerMac you have. Post a picture of the label on the back...we can help you figure it out!