Line 1-4 are working? Did you push the front buttons to switch from line to mic?(no offence, I just don't know how much you know about this stuff
). In any case, if the line inputs work, and you have output sound, then you DON'T have the old "power harness" issue(a good thing
). So back to the mic inputs, the front button needs to be set correctly. Then, if you are using a condenser mic that needs phantom power, IIRC, there is a Phantom power button for each pair(1&2, 3&4) in between the input jacks. If it STILL isn't working, you can use any number of external mic preamps between the 8 line inputs and the ADAT(lightpipe) inputs(the Behringer ADA8200 is a great budget option for that).