I have had the CTX for close to 6 years. Yesterday as I detected on several properties each time I set the machine down there was a continuous obnoxious noise. The numbers on the display screen pretty much stayed them the same so it wasn’t falsing. I kept noise cancelling to no avail. This happened as well as I was Gridding and as mentioned I was on mutilple properties. I noticed this once before but thought it to be EMI. I was using the stock coil and checked everthing I could think of so I am hopeful one of you may have a clue. Although a 61 year ol gal I am a marathon detectorist so I may have finnally wore the machine out. I guess if there is any good news I just recently received my NOX 800. Thank you in sdvance for your thoughts!