Thanks, I'll see if I can find it. I'm not a trained technician, but is there an easy way to find out if it has a defect? I have both a soldering iron and a measuring device 
Download the schematic and use meter to check track (and components) going to port from chips.
I had one with issues in past, turned out to be pin snaped inside port 2 socket.
On side note, you have tried reseating all chips? you can get some really wierd issues with dirty contacts.
