I'm fairly new to the GTI 2500 and being used to my Whites TDI it's a new ballgame. The past 2 outings I was getting 25cent signals and dug up everything from nuts, nails, pennies and other trash. I put a quarter on the ground and it read a crisp 25cents. I then pulled up a plug, threw the quarter in, put the plug in and didn't even get a signal. We're talkin' 6 inches here! I reset the machine prior to hunting so it's (supposedly) back to factory settings. My question is do I need to manually GB the machine? I was under the impression it's a "turn on and go" machine. Please bear with me, I normally use a Whites TDI.