G4 Cube VRM

[pocketscience]

I'm pretty sure the VRM in my Cube is toast. Has anyone had any luck obtaining a SuperVRM, or equivalent?

G4 Cube SuperVRM by Cuebus Upgrades on Tindie

An upgraded power module (VRM) for the Power Mac G4 Cube

www.tindie.com

Cheers,

 

[JDW]

I have not used one, but I wish to share my past experience with VRMs.

I used to be very active in the CubeOwner forums, but that site has been down for years, and sadly, Internet Archive doesn't let me browse my old posts. I did go through some emails today, from 2004 to 2007, showing I had purchased a GigaDesigns C-VRM from VINTAGE COMPUTER in Dec. 2006. I seemed to have experimented with varying the output voltage from 5.1v to 5.2v using a 75kΩ resistor because some CPU upgrades are finicky about VRM voltage and current. I found the C-VRM worked great on one of my Cubes which had a GigaDesigns 7455 1.3GHz processor, but it didn't work with my other Cube that used a Sonnet 7447A 1.7GHz CPU card, so I ended up selling it in 2007. I can't remember where I purchased the replacement (no doubt I reported that on CubeOwner.com), but the replacement VRM I have today has a huge aluminum heatsink on it to keep it cool, and it works with the 1.7GHz Sonnet CPU card.

I am reporting all those info to you so you know that there were VRMs in the past which created issues with some CPU cards, and I have no idea if such is the case with the SuperVRM you are speaking about. So unless other people can chime in with experiences, you might need to buy one to see if it works. Make sure it has a good return policy if it doesn't work.

 

[pocketscience]

Thanks James, this is helpful.

However I think I might have been wandering down the wrong path. The symptoms were very much pointing towards being power related. The machine would boot with just the HDD attached, but as soon as I tried booting with the CD, or any USB devices attached, it would start the HDD spinning and then would flash the power button LED 6-7 times ( fast, hard to count) and continually cycle attempting to boot. The video never initialised. However I tried powering it up from an iMac G3 keyboard (ie with its power button), and it's now working great. So it seems the problem is more likely the power button in the top plate of the cube..

 

[JDW]

I disconnected the button atop my Cube many years ago due to unstable behavior (e.g., fluorescent overhead lights even triggering wake, sudden shutdowns, etc.). With that button disconnected, I opted to use the button on my matching 15" LCD instead.

It's really a tragedy that the CubeOwner was never properly archived and countless years of extremely useful info about the G4 Cube is now lost forever, including a tremendous amount of my own writing. I'm a forgetful person, so I cannot recall everything I've researched and written about in the past. Back then, I foolishly assumed that my posts would be around for many years to come and that I could rely on online forums to be a permanent repository for that extremely important "individual use case" info. We also had a tremendous amount of feedback on Cube upgrades, which were great and which were flat out garbage. People today who lack access to that info may see something pop up on EBAY, buy it, then discover the things we found out in the past, but which are no longer available due to CubeOwner being down for good. It's hard to imagine that Laurie Duncan (owner/operator) would have nothing at all saved on hard drives, or that she threw them out. If she's still around or family members are, it would be great if that info could be extracted from the old hard drive backups and put online somewhere. It would save fellow G4 Cube owners countless trouble today.

If no one has noticed my Avatar yet, there's I've used that for so many years. The Cube was awesome way back in the year 2000, and it's still an incredible machine today in terms of its aesthetic design and the fact it really is one of the best PPC Macs out there due to it being so compact and fast when upgraded properly. It kind of ticks me off whenever I read about the Cube because the tech media always labels it a failure, which is marketplace related thinking which has nothing to do with the sheer beauty of the machine, compact size, and upgradability.

I only wish I could figure out how to get an SSD to work in my two Cubes. My previous attempt wasn't too long ago, and that ended in failure.

Anyway, I'm glad to see you are giving your Cube some love, @pocketscience !

 

[pocketscience]

Ohhh, that may be what has been tripping me up... I'll keep working on my restore work with the iMac keyboard, and hope that it starts behaving correctly when the top plate is back inside the Cube itself...

I did get my SSD install working last night James.. nothing particularly special. mSATA SSD in an IDE enclosure, and then one of those green adapter boards hanging off the back. The power cable needed to be turned 180 degrees, but otherwise it wasn't too bad. Mounted with a Sabrent 2.5/3.5 sled - only on one side but there's no weight in the SSD so I didn't bother with the rail from the original HDD. It doesn't move anyway..

 

[JDW]

Ohhh, that may be what has been tripping me up...

Yes, that button is terribly unfortunate. As much as I love to rave about the G4 Cube, that awesome looking power button tech wasn't fully fleshed out before the machine was released. Fabulous concept. Less than stellar execution.

I did get my SSD install working last night James.. nothing particularly special. mSATA SSD in an IDE enclosure, and then one of those green adapter boards hanging off the back.

Very interesting. Hmmm... I too used an mSATA SSD in an IDE adapter with one of those green boards, but it did not work.

I began writing extensively about what I did beginning at this post. That post is on page-2. You can then keyword-search for "JDW" to quickly and easily jump to my subsequent posts, including on pages 3 & 4. I show photos and present all the details. After reading that, if you are able to offer me some specific suggestions (only when you have free time to do so, of course), I would be sincerely grateful. But if you are too busy, please don't worry about it. It's certainly not time-sensitive. But your positive feedback today does have me encouraged and hopeful that, with your kind hand-holding and direction, I may be able to get the SSD to work in my G4 Cube after all.

 

[pocketscience]

No worries James, when I get a moment I'll take a look at that thread and comment there with my experience.

 

[trag]

It's really a tragedy that the CubeOwner was never properly archived

Lost forums:
PowerWatch Power Computing models discussion/experience
MacGurus forums General Macintosh support with some focus on memory and storage
XLR8yourmac forums Performance focused forums but also general Mac support/experience
dealmac.com forums General Mac support/experience. Some focus on what to buy, good/bad values
Content of LEMList discussion groups before about 2003 A plethora of specialized lists including SuperMac/Umax

We should never have left the comp.sys.mac... hierarchy on Usenet. Except Google is doing their best to kill that off.

 

[JDW]

Lost forums...

Not to mention all the data loss at the-other-forum-which-shall-not-be-named through the years. The goal with TinkerDifferent set out to change that, with people who run this great forum being part of the vintage computer community, rather than just one person who may pass away or lose interest or lack funds to maintain it. So long as this forum remains true to its founders intentions of keeping it in control by the community, and so long as the community keeps funding it, I do hope it will remain alive and well long after I am gone. With that said, being able to mirror online content in a smart way (not like Wayback Machine was doesn't know how to properly backup forum content, perhaps in part due to some forums locking content behind memberships and passwords) is crucial to ensure longevity of the said content.

Personally, I don't want my blood, sweat, tears and countless hours to craft posts to be wasted. I think that holds true for all of us.

Anyway, thank you @pocketscience for confirming via PM that there are issues even in your G4 Cube SSD setup with OS X Tiger. Once you get the VRM swapped out and have rock solid power flowing, if the same problem remains, such indicates we still an equally rock solid SSD solution for the Cube.

Such SSD incompatibilities remind me of my bad experience in 2011-2012 when OWC released 40GB SSDs for legacy Macs, such as for the PowerBook Wallstreet G3 PDQ which I owned. Sadly, their Legacy-edition SSDs never worked, not even after two RMAs to my address in Japan. Quality wasn't that great either, as you can see from this video I made at the time. I then made another video regarding my 2nd RMA SSD which too did not function properly. It was decided there was nothing else they could do but to refund me. OWC ended their "legacy" SSD line only 3 months later. I couldn't help but feel like I was the lone guy who did compatibility testing for them. Had they done sufficient testing prior to formally releasing the product, they should have discovered everything I did.

All said, it's not only G4 Cubes which have SSD issues.

 

[pocketscience]

My Wallstreet PDQ II is pretty happy with its SSD but pre OS X…

 

[Scorpio_ny]

I only wish I could figure out how to get an SSD to work in my two Cubes. My previous attempt wasn't too long ago, and that ended in failure.

Anyway, I'm glad to see you are giving your Cube some love, @pocketscience !

Hi! I recently joined the forums and saw your post. I have a post on the G4 Cube SSD replacement thread in which I was successful in installing a SSD in my G4 Cube. I hope there is some information that can help you out.

 

[pocketscience]

Hi! I recently joined the forums and saw your post. I have a post on the G4 Cube SSD replacement thread in which I was successful in installing a SSD in my G4 Cube. I hope there is some information that can help you out.

What OS are you running on it? My install is pretty clean using stock bits, but it simply won't boot into Tiger. 9.1 is perfectly fine.

 

[Scorpio_ny]

I am running Mac OS 10.4 and OS 9.2 on the same SSD. I can boot into either OS

 

[Scorpio_ny]

I'm pretty sure the VRM in my Cube is toast. Has anyone had any luck obtaining a SuperVRM, or equivalent?

G4 Cube SuperVRM by Cuebus Upgrades on Tindie

An upgraded power module (VRM) for the Power Mac G4 Cube

www.tindie.com

Cheers,

Have you reached out to vendor for some trouble shooting tips? I just got the same VRM to accommodate a 1.6 GHz CPU upgrade and an ATI 9200 video card. Also, do not rule out the PSU. I have one that is good and one that is dead

 

[RickM]

'evanboonie' has started an open source design of this VRM-board on GitHub: https://github.com/evanboonie/CubeVRM

 

[JDW]

'evanboonie' has started an open source design of this VRM-board on GitHub: https://github.com/evanboonie/CubeVRM

Curious...

My question to "evanboonie" would be this: how powerful is "high power"? 150% related to stock?

 

[RickM]

Curious...
View attachment 18746

My question to "evanboonie" would be this: how powerful is "high power"? 150% related to stock?

Good question.

I've opened the design in KiCAD and had a look at it. It looks like it isn't finished. The electrical design looks finished, but that's it. No Gerber file e.g. I'll try and contact evanboonie.

 

[jasperman]

My VRM in a second cube I have is pretty toasty. Some bad soldering reflow and C3 is blown. This was in a cube I just picked up and magic smoke appeared from somewhere when I plugged it in. Is there a guide to test these somehow or troubleshoot bad components? Or does someone rebuild these? I'm not looking to spend $100 or more on a replacement at the moment.

 

[RickM]

Anyone capable of reviewing 'evanbooie's design: be my guest!

 

[JDW]

@RickM
I don't have hours to spend reviewing every design choice, but I did do a quick overview with the schematic you provided and the datasheet. I didn't spot anything obviously bad, but again, I've not pondered all the design choices made.

I did take note of this table in the datasheet, however...

Then we can look at the relevant part of the schematic...

The datasheet goes on to say this:

Setting the Operating Frequency
Selection of the operating frequency is a trade-off between efficiency and component size. High frequency operation allows the use of smaller inductor and capacitor values. Operation at lower frequencies improves efficiency by reducing gate charge and transition losses, but requires larger inductance values and/or more output capacitance to maintain low output ripple voltage.

In higher voltage applications transition losses contribute more significantly to power loss, and a good balance between size and efficiency is generally achieved with a switching frequency between 300kHz and 900kHz. Lower voltage applications benefit from lower switching losses and can therefore more readily operate at higher switching frequencies up to 3MHz if desired. The switching frequency is set using the FREQ and PLLIN/SPREAD pins as shown in Table 1.

There are 3 outputs:

1. 3.3v
2. 5.0v
3. 12.0v

I personally do not consider "12v" to be classified as "high voltage," which makes me wonder why the FREQ pin was set to GND (0v), thereby making the switching frequency a very low 380kHz. (INVcc is set to Vcc which means Spread Spectrum modulation is used, with the aim of reducing EMI, which is perfectly fine.)

Nothing bad will happen with the chosen operating frequency. As mentioned above, that choice is tied to Efficiency and Component Size. And I noted that 2 of the 3 "Typical Application" circuits given in the back of the datasheet use 380kHz, while the third uses 2.25MHz.

A deeper dive requires a full read of the datasheet and analysis of each component chosen in the schematic to see why those components were chosen and how it impacts the output, but I lack time to do that. Even so, if the designer wants to come here and explain a few of his design choices, that would probably work to both enlighten everyone and put their minds at ease too.