I picked up an Ace 250 for my buddy Cliff and, because he thinks it's way to complicated, I ended up with it. Anyway, whilst hunting yesterday, I noticed that the PP AM mode was set wayyyy to negative for my ground. This got me to thinking. Previous posts stated that there were no internal adjustments to be made to the Ace 250.. sounded kinda strange to me so I decided to see what the actual case was. Well, it's pretty easy to dismantle the control box to have a look, so that's what I did. Well, whaddya know.. there ARE internal trimmer POT's on the circuit board; 2 of them. They're miniature surface mount ones. Now, the only question is, which one controls the GB? Too bad they're SMD 'cause it's a bit more difficult to swap 'em out for remote POT's. If I remember correctly, one should adjust the GB and the other has to do with the TID. Anyone know which is which? I wonder if one were to ask Garrett if they'd actually give out the info. Maybe I'll play around with it a bit and try to find out. Maybe, with a properly GB'd unit I can get a bit more depth and sensitivity to some targets. ...Willy.