Silver umax ground balance

I have read where my Silver umax ground balance can be tweaked for my location. There have been posts referring to trimmer pots, but when I opened my Silver up-there were NO trimmers or pots anywhere on the breadboard. All components were fixed components. The posts suggested schematics or posts on OTHER Tesoro detectors, but the Silver is DIFFERENT! than all the others. I think they must be confusing the SS umax with the Silver umax. Any feedback appreciated.