Dead G4 Cube

[mac27]

Well it appears that either the PSU or VRM for my Cube has given up the ghost - I'm leaning towards PSU, but not yet certain.

The Cube doesn't show any signs of life at all. Worked fine about a week ago but no dice yesterday or today. No lights/chime/anything, with or without anything connected. I do know that before, the PSU would remain somewhat warm externally while the Cube was plugged in but turned off. It would be much warmer (hot, almost) while the machine was running. Now, it's just cold even when plugged in and hooked up.

So that would suggest to me that it is the culprit. I also get nothing with a multimeter on any of the pins at the 4-pin DC connector. Unfortunately I don't have another PSU or a bench power supply to test with.

I've certainly read a lot over the years about these having issues, such as here and here, but it seems most people had an intermittent boot or other symptoms first. And have also read that opening them is a giant pain (and may even require damaging or destroying the casing). So not really looking forward to that ...

Any other Cube owners who've been through this, is this consistent with your experience or read on the situation? Just trying to determine if it's PSU or VRM first...

 

[phunguss]

Check this thread for the disassembly and pinout.

I had no problem powering a Cube or Dr. Bott DVIator with an HP/Dell 19v laptop PSU and a BUC converter to get it up to 28V. Make sure you are using at least a 150W laptop PSU.

 

[mac27]

Check this thread for the disassembly and pinout.

I had no problem powering a Cube or Dr. Bott DVIator with an HP/Dell 19v laptop PSU and a BUC converter to get it up to 28V. Make sure you are using at least a 150W laptop PSU.

Thanks. I'm definitely gonna try to repair the OEM one if I can. Did that solution end up being able to also provide the power needed for ADC, including the CRT?

 

[phunguss]

Did that solution end up being able to also provide the power needed for ADC, including the CRT?

I don't have an Apple CRT to test with. My current only working Cube is a modified version:

• GeForce 6200 AGP flashed to mac, same power consumption as a Rage 128 Pro 16MB, but no ADC port.
• SSD to replace the spinner
• SATA thin slot load optical drive from an intel iMac (with PATA adapter)
• 1.2GHz CPU with stock VRM

I do have the original GPU, and I could swap it out and test with some ADC Acrylics (I have 17, 22, and 23 models) but they are CCFL and probably don't draw as much as a CRT would. I do have a modified HP 19V 90W laptop PSU with a buck converter to 28v. A Cube should run on anything from 15-28V, but the ADC LCDs and CRT may be more picky with the voltage. Here is the 90W powering my cube under load (with DVI lcd monitor under its own power).

I don't have a finished case for it. That thin black stripe with holes is an 60% sized clone of the original, I just haven't printed it yet.

Here are my power consumption tests with my modified Cube and the original PSU. Just the PSU plugged in, Cube plugged in but not powered, and under GeekBench load.

Here are my power consumption with my 90W BUC to 28V. Just PSU, Cube not powered, idle load, GeekBench load.

I also have this 24V 150W PSU that is pinned wrong, so I will be disassembling and swapping the pins.

This one should NOT need a BUC converter to power a cube with an ADC LCD monitor (80W to spare for the LCD).

I found this diagram of some of the pinout "standards". But this diagram is misleading, as the flat edge should line up with the indent alignment node (show in the line diagram), but the photos are rotated 180. So the photo of 4PIN1 is correct for the pinout, the line art is opposite. Most other power supplies I have found (old hard drives, raid systems, Prussa 3D printers) all use the 4PIN2 or 4PIN4.

I think I may have the original CPU as well, but it is not worth it to swap that out at this point. Hope this all helps with your decision.

 

[mac27]

Thanks! Great info. I am going to see about repairing the stock PSU first, if that is not possible will explore other options ... hoping it is just a dead/blown cap or something like that.