Bought a used Optiplex 3050 SFF, Intel i5, 6500, 3.3GHz, 8GB Ram, 500GB HDD. I will use it to run Linux Mint 20.1. All is good and working fine but I have no sound. My needs for sound are just basic and reading it looks like this desktop has internal speakers but I find none. There are a lot of empty sockets on the motherboard which have no idea what they are for. Can you point me where I can get a picture/schematic of the motherboard? Thanks