Lenovo IS8XM won't turn on - broken or not?

[Steffen_6]

Hello,
I recently bought a used Lenovo IS8XM socket 1150 mainboard. It looks like this and comes from a thinkcentre m93p as far as I know.

I only connected the most necessary components and I know 100% that every part of the computer is working. Well, except for the mainboard. If I try to start it, nothing happens. As if the mainboard is not connected to the PSU. Though it does a little creaking sound if I connect the two pins to start it up. But I don't know where that sound might come from as there is neither a speaker, nor a harddrive or optical drive connected to the board.
I know this is very little information to work with and I'm only asking because this mainboard is from a prebuilt system. I thought that it maybe has some security features that prevent it from turning on that I don't know about. Its has a Cover presence switch connector that isn't connected to anything but I don't know if that's it.
Here is a manual for the prebuilt PC that includes some information about the mainboard: http://cc.cnetcontent.com/inlinecontent/production/e4/e43917bd59eb/cnet_7a7b_doc.pdf
I would be very thankful if anyone has an idea what would be wrong with it, otherwise I would just assume it is broken

 

[mbarnes86]

Hi

Did you use a lenovo power supply designed for this motherboard?

The main motherboard connection seems to have 14 pins instead of 20 or 24 pins

regards
Mike Barnes

 

[Steffen_6]

Hi

Did you use a lenovo power supply designed for this motherboard?

The main motherboard connection seems to have 14 pins instead of 20 or 24 pins

regards
Mike Barnes

Hi!
No, but I did use adapters. One 24 pin to 14 pin and one molex to 4 pin for the 4 pin in the upper right corner. For the other two 4 pin connectors above the 14 pin I used the two 4 pins my PSU already has