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Unexpected surprise in a G4 cube...

lobust

Active member
Bought a clean cube a little while ago on ebay, came with a really nice boxed 20" cinema display, and I was really pleased to get one in nice cosmetic condition.

I have been struggling to get it to boot properly, I had to the point where it would boot an existing 9.2 installation to loading exts, but then freeze, and it won't boot off my OS9 retail cd's either, so I haven't got it to boot into an OS yet.

I decided this evening to strip it right down so I could try a different IDE cable, this one has a few nicks and I suspect a possible short or break. I decided while I had it stripped down I would put some new thermal paste on the cpu.

And I found this:

IMG_0399.JPG

:D:D:D

There is a fan in the base, so I had an inkling that something was perhaps not stock, but I did NOT expect this!

It's currently on what appears to be the stock VRM. I do already have an artmix one on order as I want to play with other video cards, but not arrived yet. Is it safe to run this on the stock VRM?
 

Rick Dangerous

Well-known member
Sweet...helluva find. I did love my cube but had constant issues with it; so eventually parted ways.

They can be made reliable if you tinker enough; good luck with this one and enjoy!
 

Byrd

Well-known member
It's currently on what appears to be the stock VRM. I do already have an artmix one on order as I want to play with other video cards, but not arrived yet. Is it safe to run this on the stock VRM?

Best surprise of all! Nice upgrade. The artmix Cube VRM is not compatible with all configurations, but if you're going to source a much more powerful GPU I'd hold off on installing all until you get the artmix to test.

Was it a slim 80mm fan - they're not great, there are much quieter more effective CFM 80mm full thickness fans out there you can fit in the Cube chassis with a little bit of work.
 

lobust

Active member
Thanks for the comments :)

I made a usb boot of the tiger dvd and it booted off of that, so I hooked up a mini-pcie ssd>44pin>40pin and installed it on that, and it booted and ran fine but needed the sonnet firmware patch as it was showing 0Mhz cpu.

I had a weird false start when trying to boot the cube in programming mode, where it went into programming mode normally, but then wouldn't boot any further. After a lot of panicking and messing around I got it to boot into the tiger usb again and discovered that my tiger partition on the ssd was just gone, disk utility showed a blank drive with no partitions. I don't know what happened there. I reinstalled and tried again and it all went smoothly the second time...

Now see a sweet "1.7Ghz G4" in About this mac and system profiler.

I have a radeon 7500 in there right now. It's TDP is close enough to original card that I didn't think it was a huge risk to run it with the stock vrm. I have a R9000 waiting in the wings too for when the artmix vrm arrives, but if I put that in it will likely be the limit as I don't want to lose the ADC connector.

The fan is a slim one, looks to be the one originally supplied with the encore from pictures I found on newegg. A panaflow. It seems actually pretty quiet, but more airflow certainly couldn't hurt. The cpu itself seems to run pretty cool. I might in the future consider ways to move the gpu into the hard drive bay where it can get more airflow. I guess would need a custom riser cable and taking the display connectors off the board, could be a fun project..
 

herd

Active member
Nice find on the Cube and CPU upgrade!

I didn't think it was a huge risk to run it with the stock vrm.

How hot does the 5v section of the VRM get? I'd say you're at the limit with that CPU, and you probably already know that the VRM failure mode is catastrophic. You could add some heatsinks to the VRM to help.
 

lobust

Active member
Nice find on the Cube and CPU upgrade!



How hot does the 5v section of the VRM get? I'd say you're at the limit with that CPU, and you probably already know that the VRM failure mode is catastrophic. You could add some heatsinks to the VRM to help.
Thanks for the warning, it's my first cube but I did a lot of reading before I bought it, so I know what the result of burning out the vrm is.

Impatience and the desire to tinker would not allow me to leave it alone until I got the new VRM!

I have tried to be careful not to do anything to pull any real power for the time being - no benchmarks, no games, no 3D anything. Just enough to get it booted, do the firmware update and check the system profiler.

The reason the 7500 is in there right now is because so far I have four potential cards to use - a stock R128Pro, a stock Geforce2MX, the 7500, and the Radeon 9000. The R9000 is clearly a no-go until the new VRM is installed, and the Rage 128 that came in the cube has some intermittent fault that prevents it booting about 70% of the time. So I am left with the 2mx and the 7500, and the 2mx seems to dissipate a fair bit more heat than the 7500, even just idling on the desktop.

Not very scientific, but more heat usually means more power, so the 7500 seemed like the safest bet. The mosfets on the VRM module do not seem overly hot so far, at least not uncomfortable to the touch...
 

Byrd

Well-known member
I wouldn't worry too much about blowing your Cube with those upgrades, just enjoy - can you confirm the Sonnet G4 you have was definitely designed for the Cube? Some people put in desktop CPUs which had higher thermal output and voltage requirements.

I used a Gigadesign G4 1.5Ghz, Geforce 6200 AGP (with fan), 7200 RPM HD, and stock Apple VRM for years - it's still going fine. Heatsinks on the VRM (you may have also read about a mod where people added "missing" VRMs that didn't appear to do much). Amusingly, the Gigadesign C-VRM did not work on the Gigadesign CPU I owned.
 

lobust

Active member
I wouldn't worry too much about blowing your Cube with those upgrades, just enjoy - can you confirm the Sonnet G4 you have was definitely designed for the Cube? Some people put in desktop CPUs which had higher thermal output and voltage requirements.

I used a Gigadesign G4 1.5Ghz, Geforce 6200 AGP (with fan), 7200 RPM HD, and stock Apple VRM for years - it's still going fine. Heatsinks on the VRM (you may have also read about a mod where people added "missing" VRMs that didn't appear to do much). Amusingly, the Gigadesign C-VRM did not work on the Gigadesign CPU I owned.

That's reassuring thanks!

I don't have much to go on to say whether it's a cube processor or not. The SG4K designation doesn't appear anywhere in Sonnets knowledge base or manuals that I can see. Cube processors are apparently designated on SG4C, but this old newegg listing shows the SG4K part in the pictures, and the fan that is in my cube is the same fan that's pictured, so...

 

lobust

Active member
I have the Artmix VRM installed and all good, got the cube online and launched safari, and got a few pages in and soft hang. As in it all locks up, but the gradual lock up with spinning beachball that comes with a failing hard drive. Something is not right with the SSD that I'm using. Seems any kind of real disk activity causes it to drop out and the OS eventually locks up because it can't access the disk.

I am also mindful of the weirdness of it being suddenly blank when I was trying to update the firmware.

Before I go and buy a different drive, what are the odds that this is not the drive itself causing this? Motherboard caps old enough to be suspect on a G4?
 

herd

Active member
How does the CPU connect to the heatsink? Does it use the original copper heat plate and spring clip or does it have something different from Sonnet? Does it make good contact, thermal paste, base fan, etc? Basically I'm wondering if the CPU is getting too hot, because it sounds like it works at first then locks up when it gets warm.

Do you have a stock (or different) CPU that you could try? Any of the single 400 to 533MHz G4 boards would work. It won't be as fast but it could help you track down the problem.
 

lobust

Active member
How does the CPU connect to the heatsink? Does it use the original copper heat plate and spring clip or does it have something different from Sonnet? Does it make good contact, thermal paste, base fan, etc? Basically I'm wondering if the CPU is getting too hot, because it sounds like it works at first then locks up when it gets warm.

Do you have a stock (or different) CPU that you could try? Any of the single 400 to 533MHz G4 boIards would work. It won't be as fast but it could help you track down the problem.
I made a new post in the proper subform about this as I have been working on it; https://68kmla.org/bb/index.php?thr...when-ethernet-is-connected.38641/#post-417773

I discovered that it's some how related to the ethernet. I can launch every app on the drive simultaneously and load everything right up no problem, the gradual lock up only begins after I plug the ethernet cable in.

The cpu used the original copper heat spreader, foil and spring clip. I removed the small foil on the die side as it was damaged, and honed the contact area on the heat spreader instead and used some arctic silver compound. I'm pretty confident there is good thermal contact. Unfortunately I don't have a stock cpu to try, but I am on the lookout for one.

If you have any ideas about the ethernet I'd be really grateful if you'd have a look at my other thread.
 

Byrd

Well-known member
Did you clean all the black crud on and around the heatsink when foil was removed? I had to use Acetone to get mine off. Did the same setup freeze with the stock VRM - as noted the Artmix VRM is not the gold standard in all situations (the Gigadesign C-VRM is more or less the same design).
 

lobust

Active member
Did you clean all the black crud on and around the heatsink when foil was removed? I had to use Acetone to get mine off. Did the same setup freeze with the stock VRM - as noted the Artmix VRM is not the gold standard in all situations (the Gigadesign C-VRM is more or less the same design).

Hi, yeah the problem appears to be independent of the VRM - same on both. If you didn't see my other thread, I got it working with a wireless bridge instead of direct connection to the router. I don't know why, but it works now.

On the heatspreader, I left the foil on the heatsink side, I just removed the small piece on the die side. The heatspreader is a fairly poorly made piece, the surfaces are rough and not very flat. It's solid copper with some kind of graphite plating. The foil is some kind of readily deformable heavy metal, clearly intended to compensate for the poor flatness of the heatspreader. It's a bit shoddy really, I would have hoped for better in a premium engineered product like the cube. Everything has a price point I suppose. I scraped the die side back to bare copper and good flatness and applied thermal compound directly between the heatspreader and die.

I haven't installed anything to monitor temps yet, will do that this evening.
 
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