Through their site: https://www.artmix.com/PowerMac_G4_VRM.html
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Upgrade G4 Cube
- Thread starter Wouter3
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This VRM looks promising and is more powerful so would fit my needs. As you have one, does it include a plug to connect an external 8 cm cooling fan? I tried to pose that question on the site, but their email system does not have a send button, so the message got stuck on their site without being send.
I would first try to fix the Cube VRM though. Chances are the logic board is dead too, so if you get the Artmix VRM you could just end up with a $150 paperweight. You can put some heatsinks on the VRM to keep it a bit cooler. The VRM will always run hot.
It literally says "Including Cooling Internal FAN" on the website. I still would not buy the VRM, because as I said, it's possible your logic board is gone too. Also the connector is still not a standard one. I'd just not bother with a fan until it actually works.
I have posed the question to a repair shop, but I do'n know whether they manage to get it fixed. I will sure await their answer first. Is there a way to check whether the VRM could have taken the logic board with it by measuring the resistance of the drain and source pins (if I would know where they are).
Didn't know this. The last news i read about this was the exact opposite. But if this is the case i would happyly spend those 150 bucks as the stock VRM, even a "strenghtened" one, is alway the weakest link in the chain.
Further i would always prefer a freescale CPU like the 7447a/7448 over a 7450/55-based one like the Sonnets, as they are known to run cooler and as far as i know also draw less juice. Even with a stock VRM and without VRM-bypass a 7447a @ 1.6Ghz should run absolutely fine. I used this combination for years without any glitches. As for the temperatures, Bresnik’s hardware monitor will not help you much as the G4s do not have any temperature sensor. The only solution ever to get temp-readouts of G4 CPUs has been Powerlogix’s CPU Director, only working for freescale upgrades and only up to 10.4.9.
For the GPU, as mentioned earlier, your best choice is the GeForce 6200. For power consumption reasons i would suggest to avoid the Radeon 8500/9000 Pro as well as the GeForce 3. And no! There ist no 6600 running in a Cube! At least not without external power or as minimum an Giga-C. As well as the 9800 Pro, this card should be able to kill a stock VRM instantly (if it boots anyway).
As last, i wouldn't suggest to take the fan's power of this small connector from the VRM, but instead split it out of the molex. And, for noise-reasons, i woldn't use 12v but instead 7v (using the 12 and the 5v lines) or even 5v. Even a fan running (nearly inaudible) at 5v is much better than no fan at all. But in no case the fan power should have been the reason for your dilemma.
Here's the datasheet of the MOSFETs: https://www.vishay.com/docs/71188/71188.pdf
I would assume S is source, D is drain and G is ground. So basically, just measure any of the 2 middle pins on each side.
Yes. In this case there should be some mofset somewhere close to the power connector looking somehow like the one on the picture you posted. But i do not know, if this is the only component getting dammaged "in case".
I measured the 2 middle pins on each side of the 3 MOSFETS. On the right one (the most black burned one) there is a resistance between the 2 middle pins on each side (between pin 2 - pin 7 and pin 3 - pin 6 on your pdf sheet) For the other MOSFETs the reading is "zero resistance"
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I think the Molex source would be the easy one. But I would still need to see whether the logic board is still alive. It didn't stop running while I was using it. I switched off the machine in a normal way, but only afterwards while the powercord was still connected, it burned the VRM. That is why I hope the logic board is still alive, although I see a red LED on the motherboard when I touch the power button.
I will first try to get the VRM fixed. If that doesn't work I might try to get this Japanese VRM and see from there
I will give the motherboard a thorough check tomorrow and let you guys know
Well, I think your logic board might be fine. Interesting that it does anything at all though, I think if it was dead you wouldn't even get a red LED. I'm no expert, so it very well could be dead. Buy some replacement chips (there is a newer version that should be completely compatible with the old ones) and put them on. There is another set of Si4840DY MOSFETs on the VRM board, so you should get at least 8, even if the Cube only has 6, at least replace the 6 first then you can add another 2 onto the empty pads if it does work. I suggest doing it yourself as it's not exactly hard, you just need a hot air gun.
...but you mentioned some random black screens and HD-spindowns while it was running before. These are clear indicators of a heavily overloaded or dying VRM! I had things like that, experimenting with a far too demanding GPU, when putting 3D-load to the card. It could only be "cured" using the Giga-C.
9800 Pro you say? Found this by complete accident: https://hardforum.com/threads/project-supercube.796759/
Of course, this guy modded an ATX PSU onto the Cube, but it does show it will work. A GeForce 6600 will most definitely work, and possibly even fit inside the case. Of course you will need a custom VRM to handle it, but why would it not work?
I had some 6600 GT running in an experimental state in an open core of a cube with external molex power provided. It fits in and can even drive a 30" Cinema HD Display. But for daily use it’s an absolute NoGo. First you have to find one which has the AGP 2x key in front like this one. As they are AGP 4x/8x cards most of them only have the key in the back of the connector, meaning they don't even fit in the cubes AGP. But in the very first place all of these cards, needing additional molex power, which are Radeon 9700/9800pro, Geforce 6600GT/6800XT, are running far too hot for the cube's narrow genuine case! In the wider Powerlogix cases they might work under certain circumstances. But in the cubes own case they will overheat within minutes. Even with a big fan running at full speed. There is simply no space to get fresh cool air for a beast like this.
Now I wish I had bought a Cube... I think I could get at least a Radeon 9600 working in it without overheating with a few cooling mods.
Thanks for your suggestion. I watched a video on Youtube on soldering and it was an eye opener for me. I will give that a try. However, I still will consider to buy the Japanese VRM as it provides sufficient power for my 1GHz CPU. I will now start checking my logic board on any burnmarks
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I remember that I had these outages shortly after I bought the Cube and had not installed the faster CPU. So the VRM was clearly on its edges already. You mention using a Giga-C. What is that and does it compare to the "Japanese" VRM that JMilan0302 referred to.
I just checked the logic board and the video board. Both didn't show any signs of burned components. As I said earlier I would like to order the "Japanese" VRM, but also like to repair the burned one. I just found the MOSFETS on ebay so I might order a few. Would this be the proper one: https://www.ebay.nl/itm/VISHAY-SI41...869160?hash=item2a30e3e928:g:W88AAOSwXYtYuIw2
They are 30V while your sheets mentions 40V?
In searching on their website I found 3 40V MOSFETS: https://www.ebay.nl/sch/m.html?_odkw=N-Channel+40-V+(D-S)+MOSFET&_ssn=petelox&_osacat=0&_from=R40&_trksid=m570.l1313&_nkw=N-Channel+40-V+(D-S)+MOSFET+Si4840DY&_sacat=0
But they all have different SI numbers.
Which one could fit the VRM?
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It’s the VRM-board shown in the picture in an earlier post in this thread. It once was sold by Gigadesigns, another brand of faster CPUs, to support their upgrades. I do not know the specs. But the board layout looks somehow similar to the artmix STRATOS. So maybe the STRATOS has been "inspired" by the Giga-C and also the specs are similar.
I looked up Gigadesigns and got at: https://everymac.com/upgrade_cards/gigadesigns/. but that describes the upgrades for a number of Apple computers, but it lacks the Cube. Also I see a price for the different components, but not where to order them
You might have missed this one.
As for Giga Designs: They vanished from the market a long time ago. So the Giga-C should not be available new anywhere. And they even appear close to zero on ebay. Looks like people having the few ones still don't give them away anymore.
Yes unfortunately. Lucky me I managed to get a Sonnet 1GHz board for the Cube recently and that works great without modifications. For the VRM: looks like mine was dying from the beginning and the new CPU only excellerated its demise. Now that my logic board looks OK I will order the $150 "Japanese" VRM.
The Cube is there albeit at 1.3GHz only. I have one in mine but it runs at 1.6Ghz. Single CPU, so it only needs the supplied fan and not the custom VRM that came with the dual CPU version.
That Everymac page is incomplete.
But I assume, they are no longer for sale anymore. So I stick with my 1 GHz Sonnet version. Which is not the fastest, but the Cube is slow to any standard of modern computing. I use it for fun once and a while and save it as a collectors item.
...but not as slow as the Ghz might make one think! As the Sonnets have 1Mb cache while the 7447as only have 512k, depending on the task beeing performed, th 1,2Ghz Sonnet is as fast or in some cases even faster than a freescale running @ 1.6Ghz. With one exeption: the 7448 also has the bigger cache and is for sure the fastest and most efficient G4 around. But it should be absolutely impossible to find an upgrade equipped with one (or even two!) of those today.
If you are interested: I have in some other forum made a complete two part documentation of all the upgrades i made to my Cube and a third part for an additional CPU-upgrade with an dual 1.6Ghz card. I think, by now it is somehow "maxed out". Here are the parts:
Part one
Part two
and the CPU-part
Only thing: All the stuff is in German. So i hope you understand.
Part one
Part two
and the CPU-part
Only thing: All the stuff is in German. So i hope you understand.