Help, mini-itx board will not power up with 12V P4 4pin

tnynyn · Post by **tnynyn** » Thu Nov 06, 2008 9:05 am

Hello everyone,

Needing some guidance regarding a Commell LE-565 mini-itx motherboard which is based on Via chipset and Eden cpu. It has an onboard p4 power connector and a 12v dc jack connector. I wanted to use a regular atx psu w/ p4 connector to power the board, but it will not power on at all. I have only the p4 connector hooked up, but when i try to power it on, nothing will come on, not even the psu.

I tried this with 2 different psu (antec and sparkle) which works with other systems. Also tested in two different cases.

Any ideas?

Spare Tire · Post by **Spare Tire** » Thu Nov 06, 2008 11:08 am

dont you need to plug in both the 20pin AT power and the 4pin p4?

EDIT: nevermind, my bad, i thought it was a mini-itx, looks like a pico or nano-itx
i see a molex connector, how about that one, plug it in (check your manual first of all i guess)

tnynyn · Post by **tnynyn** » Thu Nov 06, 2008 11:16 am

i believe that is for output (from manual)

it is a mini-itx actually, however it does not have any other power connectors other than a 12v dc jack and a 12v p4 4pin.

i dont have a 12v ac-dc adapter (~$30 on ebay for a generic) but I'd like to use a internal psu that i have already. if it doesn't power on with the p4 4pin, im guessing it wont power on with a 12v ac-dc adapter? dont wanna blow 30$ if its a dead mobo.

tehcrazybob · Post by **tehcrazybob** » Thu Nov 06, 2008 4:07 pm

The problem you're running into is that a modern PSU won't provide power on anything but the standby rails unless it's plugged into a motherboard via the main ATX connector. You can trick the PSU and bypass the issue by shorting the green wire in the ATX block to any of the black wires.

tnynyn · Post by **tnynyn** » Mon Nov 10, 2008 10:40 am

thanks tehcrazybob,

that did the trick. looks like its the only solution for my 24/7 server.