I have a Minelab Excalibur 1000, have used it with great success for four years. Most all of my hunting is beach hunting. It came with a rechargeable battery pack, which gradually got weaker until late last year wouldn't hold a charge long enough to hunt with. I ordered a battery pack that works on 8 AA batteries, to try that. The first set of 8 lasted a really long time and performed well. Three weeks ago that set started making a noise like a dog barking at me, so I correctly assumed the batteries were getting low. I changed them out and started hunting again. I hunted for just a few hours and turned the unit off, placed it in my truck to change location, and when I took it out and turned it on, all I could get was a solid, non changing for any reason, mid level tone. I could not adjust it out, it was just continuous. I thought maybe it was poor batteries I had installed, so I changed them out for new ones again, and the unit went right back to working great. Then yesterday, same thing, just that annoying solid mid level tone. These batteries had only three hours or so on them,, and they were brand new when I took them out of the package. So, my hunt was over quickly. I brought the unit home and cleaned it up as always, and this morning I try it again and it's working again. I pulled the batteries and checked them, and they were pratically fully charged, hot, so I know it was not the batteries. I cannot understand what the problem is and am wondering if anyone else has had a similar problem. Dakota J in OBX-NC desperate.......