I have a Jetway NC9 8-525 E-LF motherboard and it is kinda weird because it does not use an atx or the 4 pin power. It only has the 12v DC plug in the back. I have seen quite a few posts on here about powering them in a car and here is what I did:
I ordered the DC-DC intelligent USB PSU form mp3car.com to use to power that computer and to make it start up and shut down with the ignition.
because there is no ATX or 4 pin power on the motherboard i realized that the power had to come into the computer from the 12v 2.5mm jack in the back of the motherboard.
To power this beast i took a 5V AC Power supply and cut the wire off leaving only a wire and the 2.5mm male barrel connector and soldered this wire to the yellow and black power wires that are supposed to goto either the ATX or 4 pin power connectors on the motherboard. plugged it into the back of the computer, hooked it up to a 12v bench power supply and voila.....power to the computer.
now for the smart start up/shut down controller
I wanted to be able to take the computer in the house and work on it if i needed to so what i did was took a 2 pin power wire from another old computer and put it on the DC-DC power supply. I drilled a 1/4" hole on the output side of the DC-DC power supply housing and the other side of the wire i cut from another computer i soldered to a 3.5mm female audio jack that i installed on PSU housing. on the Jetway motherboard i spliced into the power switch and soldered a wire to each of the leads. The other side of the wires i soldered again to a 3.5mm audio jack that i drilled a hole for on the back of the case. now for the cool part. to get the smart start up/shut down to work i simply took a 3' aux input cable with two male 3.5mm ends and plugged one end into the DC-DC power supply and the other end into the computer------and it works. The good thing about this setup is if i need to take the computer into the house i simply disconnect both cables from the back of the computer and i can take it into the house. Since i spliced into the power switch in the computer, it still works with a standard wall PSU that i bought and use the on/off button on the computer.
I hope this helps with others who have this type of motherboard. the PSU cost like $65 and the 3.5mm female jacks cost like $5 at radio shack. The power supply i cut to plug into the back of the motherboard i had so it did not cost me anything. The voltage of the power supply does not matter. The only thing that matters is that the male end will fit into the female 12v connector on the motherboard. Im sure everyone has extra power supplies laying around the house.
If anyone needs pictures, i can upload them.