I've never had trouble with my ground balance, auto, tracking or manual with my 705. I leave the gb tracking on and my settings have no need to vary much as I'm usually hunting simular sites. Sometimes I just turn on and go. Usually though I at least do this - Power on, check sensetivity and I have to run sens at no more than 22 with the digger coil however I can run the 5x10 18.75 khz coil at 25-27. I then check all the other settings. I then imediately do an auto noise cancel. Now that works for me and what I've allways heard is the 705 is remarkable with noise cancel.
Now yours, Have you done this with another coil? Also be sure to hold the machine like you would if your detecting. I do hold it up about 10 - 12 inches because the coil is like a antenna. Holing it up as I do ensures it'll pick up any interference if some exists. If you make contact with the ground it may work but the ground could impede a noise signal so I hold mine up while auto noise canceling.
If you've tried another coil and that doesn't help go to a place like near a wifi or overhead power lines, have the machine on before you approach the noise source/EMI. Walk to the source until you hear interference and then run auto noise cancel to see if its working.
You've probably checked all obvious things like loose connections. Some guys can't have a cell phone on them at all or they have trouble. Depends on the phone and wether or not its set to auto update. I hope this helps. Soon others will chime in here and we' ll figure it out. Let us know.
Tin
