New Samsung EVO 840 not working in iMac (Late 2009) second SATA bay

Hi all,

read many articles about EVO 840 and Mac Problems so far, nothing that fits my problem :-(

I have a Late 2009 Core2Duo 21.5" iMAC running fine - MacOS 10.7.5. I bought a Evo 840 500GB last week and a SuperDrive replacement bay for that specific model.

Before opening my iMAC (...arghh..., afraid...) I put the SSD in my Lenovo Notebook and it is working fine. I used SSD Magician to make sure that the latest Firmware EXT0BB6Q is installed.

Than I put the SSD into the external Case that should later house the to be replaced Superdrive - and the SSD was not shown in Disk Manager. I thought this was a problem of the bay maybe - but another 2.5" SATA disk was working fine in it.

Now I put the SSD in my Mac and . . . it is not even recognized :-((

"System Information" shows only the internal 1TB SATA under "Serial-ATA Devices - NVidia MCP79AHCI". Under the second NVidia entry there appears nothing.

So I really need a good hint apart from cabling or firmware. Or maybe my MacOS is too old for this disk - for whatever reason. Or it is only supported on the first SATA Port.

Maaaany Thanks in advance from northern Germany

Oli