Hey guys was recently given a pair of Mk3's and am trying to sort out what kind of mods have been done by previous owner. On my power supply board, looks like it says "Vintage Electronics" or "Vintage Electron". Kind of hard to read. Looking from underneath mounted in the top right hand corner is what looks like some sort of pot with a fine, almost jewlers screw head. I am going to guess that it's a balance adjustment of some kind. Any thoughts would be appreciated. Thanks