If you ever tried to use Atheros MiniPCI module (ie. Wistron Neweb CM9) in older computer, you probably failed. The reason is old revision of PCI bus. PCI 2.2 introduces 3.3 volt availability for peripherals usage. The new Atheros MiniPCI modules require this feature. If you use them in PCI reduction in older motherboard, you need to find 3.3V source somewhere else. There are few ways how to get around this, one of them is described in this article.

I recommend you to start with reading PCI 2.1 vs PCI 2.2 differences description - everything important for this hack is covered, there. Then you need to buy MiniPCI-PCI reduction (I bought this one from i4), MiniPCI Atheros card (I’m using Wistron Neweb CM9 MiniPCI card), two pieces of silicon rectifier diode with maximum amerage 1A, 330Ω resistor, spaghetti insulation and soldering equipment. When you’ve got all of these things, you can start ;).

Bellow you can find hires photo what and where you’ve got to solder (details about pin numbers are described in the schema [linked above][PCI 2.1 vs PCI 2.2 differences description]).

Click on the image to enlarge

What are disadvantages of this technique? Well, there is one problem - voltage on the 3.3V part of the card is 3.58V which is little more than it should be. The result of this matter can be higher output power of the card and possible damage. But I’m using this hack on more places and I never saw destroyed Atheros card or motherboard as a result of this modification.

If you want to find out more about other possibilities of running Atheros cards on older motherboards, I recommend you to visit Petr Simandl’s webpages dedicated to Atheros cards (Czech version). English version is much shorter and doesn’t contain some information.

Thanks for help with the design and construction goes to my father because I’m lame when I’ve got to do something with electrical devices construction or soldering :).

Legal disclaimer: I don’t guarantee that this will work on all cards

• newer PCI specifications are not just about the voltage. Everything you do is at your own risk.