PowerMac G4 Cube hates to restart with Video

[JohnnyPhantom]

Hey Everyone,
I have a PowerMac G4 Cube (I absolutely LOVE this model) and I have it on a table in my office at work as a display piece (as well as some retro gaming on lunches) I have the factory CD's that came with it as well as just about all of the Apple OS installers in a cd binder. I ran the Apple hardware test on the longer diagnostics with no problems found. If I do a recovery from the G4 Cube recovery CD or install a fresh install of Mac OS 9.1 or 9.2.1, I'll get my issue where the machine boots, chimes, looks and works just fine, but, if I restart or shut down. It'll boot, chime, but no video. Also, if I boot into OS 9 and let the machine go to sleep, I can't wake it up. If I disconnect the power and plug back in and try, video works again and it boots. I'm using an Apple ADC monitor and the original Cube Speakers (happens without the speakers as well). I did notice if I install OS X 10.4, works as it should, it'll sleeps and restart just fine. I'm going to try testing a few other pieces of hardware (RAM and such), just curious if anyone has any ideas. I also did a reset-nvram and a pram reset. It's running the latest 4.1.9 firmware as well, PRAM battery measures at 3.61V

Thanks everyone!

(Update: forgot about the PMU, resetting that now and testing, also taking this time to upgrade to a SSD)

 

[JohnnyPhantom]

Looks like PMU reset solved it, so if anyone else has this issue, hopefully they stumble upon this thread and it helps them out. I got the SSD installed, a lil quirky, but working. I may look for a better solution in the future. The SSD bracket i printed out works fine, but could use some fine tuning to match the IDE to SATA adapter I got.

 

[JohnnyPhantom]

Never mind issues back... hmmm....

 

[François]

Did you test it with another monitor? Maybe the issue is not with the Cube…

 

[JohnnyPhantom]

Did you test it with another monitor? Maybe the issue is not with the Cube…

That’s what I’m thinking. I’ll test that tomorrow. Took the ssd out back to the mechanical for now

 

[JohnnyPhantom]

Did you test it with another monitor? Maybe the issue is not with the Cube…

Looks like a standard VGA monitor works fine, sleeps, reboots like a champ. So I guess issue could be the ADC monitor (any repair guides?) the video card, the power supply of the cube, or anything else that could supply power or video the the ADC monitor. hmmm...

 

[François]

IIRC there’s a direct feed from the power supply plug on the cube to the power lines of the ADC connector on the video card. Meaning that the Cube doesn’t manage the ADC power at all.

 

[JohnnyPhantom]

IIRC there’s a direct feed from the power supply plug on the cube to the power lines of the ADC connector on the video card. Meaning that the Cube doesn’t manage the ADC power at all.

I believe you are correct, I'm pretty sure I saw that in the Apple service guide, so if you're correct in that the cube doesn't manage the power, and is more of a pass through, than I guess that would narrow it down to the monitor itself or the cubes power supply maybe? maaaybe the DC to DC board if the ADC power goes through that?

 

[François]

I don’t think the ADC power goes through the DC-DC board. It goes through the short cable that goes from the motherboard to the AGP riser card. The connector for this short cable on the motherboard is directly wired to the power supply plug of the Cube.

I think it may be a problem with the video card and/or the monitor losing the (software) connection to each other?

(If it were a power problem, you’ll see it with the power led on the monitor)

 

[JohnnyPhantom]

I grabbed a 22" Apple Cinema Display (ADC, July 2000) last night from facebook Marketplace for $15 and tested today. It works amazingly and reboot/shutdown /sleep issues are now gone regardless of what OS I used. So looks like the ADC monitor I was using was the issue (the 15" Apple Studio Display (LCD) July 2000) I got the SSD in the machine now using a Startech IDE2SATA adapter (which works perfectly!) so the Cube is up and running with a SSD now and works perfect! woo!

 

[François]

Enjoy your Cube! They’re awesome little machines.