omidimo
Well-known member
Be aware though that if your VRM did blow it is likely that it took your logicboard with it on its way out.
Have had this happen twice recently! Dying VRMs are harbingers of doom.
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Be aware though that if your VRM did blow it is likely that it took your logicboard with it on its way out.
As far as I know, Artmix is a one man company. I bought several items from him.They still are selling them:
Is there anything that can be done to protect the original VRM's-- Mine is still working but I'm wondering if I should buy one of the Artmix VRM's for my Cube.
Some Cube CPU upgrades require the VRM bypass wire even with a custom VRM. Upgraded VRMs were useful for powering better graphic cards and could power some CPU upgrades, not all, but a VRM bypass is always preferred and in some cases necessary.Also, does the Artmix VRM work with all CPU upgrades? The Powerlogix VRM did not, and I ended up selling mine as it was patchy, to say the least.
From the old Cubeowner knowledge base:Is there anything that can be done to protect the original VRM's-- Mine is still working but I'm wondering if I should buy one of the Artmix VRM's for my Cube.
There are empty pads in the Cube's VRM to add an extra MOSFET and it shouldn't be difficult to solder if you have any experience soldering SMD components. The benefits of doing so were still debated when I last checked cubeowner but IIRC the theory that the lack of the second pull up transistor were related to production shortages and not a last minute design change was gaining traction.[SIZE=10pt]Adding extra transistors to the Apple VRM[/SIZE]
[SIZE=10pt]For the Apple VRM, the 3.3 and 5V voltages each involve a bank of power MOSFET transistors; using a pair to pull down and a singlet to pull up. It is the singlet (Q9 or Q7) that usually fail, and since there is an empty space to add a sibling, the idea is to solder in extra Si4840DY units (~$1.50 each). This has been done (requires a steady hand and good soldering skills), and the resulting unit tested and found to be functional in a cube.[/SIZE]
[SIZE=10pt]However, there remains the question as to why Apple did not double up on the pull up transistor, and a line of reasoning that the resulting reduction in switching speed may counter any benefits.[/SIZE]
[SIZE=10pt]All this needs to be considered with the fact that a failed VRM often destroys other parts, which is both reason for toughening it, and reason for not risking the modification.[/SIZE]
[SIZE=10pt]The modified unit is best tested outside the cube, where the enable pin needs to be grounded to turn it on. A superior alternative is simply to purchase the proven stronger GigaDesigns VRM (~$100)[/SIZE]
[SIZE=10pt]This is a 'do at your own risk procedure', as there is the possibility of not only destroying a good VRM, but also of destroying the other parts it is connected to.[/SIZE]
I would be interested in seeing the pictures-- Thanks.Some Cube CPU upgrades require the VRM bypass wire even with a custom VRM. Upgraded VRMs were useful for powering better graphic cards and could power some CPU upgrades, not all, but a VRM bypass is always preferred and in some cases necessary.
From the old Cubeowner knowledge base:
There are empty pads in the Cube's VRM to add an extra MOSFET and it shouldn't be difficult to solder if you have any experience soldering SMD components. The benefits of doing so were still debated when I last checked cubeowner but IIRC the theory that the lack of the second pull up transistor were related to production shortages and not a last minute design change was gaining traction.
I can attach pictures of the empty PCB pads if you're interested.
Here is it:I would be interested in seeing the pictures-- Thanks.
I 'm also thinking of making this heatsink for the VRM from some aluminum stock.
http://applefan.tistory.com/10
Interesting stuff. Not a Cube guy, but upgrades in general . . .From the old Cubeowner knowledge base:
There are empty pads in the Cube's VRM to add an extra MOSFET and it shouldn't be difficult to solder if you have any experience soldering SMD components. The benefits of doing so were still debated when I last checked cubeowner but IIRC the theory that the lack of the second pull up transistor were related to production shortages and not a last minute design change was gaining traction.
Good for you! It's always good practice to not simply take something at face value without thinking about what might be underneath the surface (often times, it doesn't take much to find out if you know how/where to look). It must've been... interesting... getting those skills "drummed into" you, though.. . . . can't help myself. Healthy skepticism in observation/analysis/problem solving was drummed into me by the Jesuits at an impressionable age.