Huh, i dont know. I know that when i go to ground balance mine sometimes it acts funny and gives off a noise, then nothing. I think my depth button might be messed up, but so could the ground also. I know that if its not a coin, and you go over it a couple of times the CZ wont "make up its mind" on what to call it. Which in most cases = Nails are other crap. Any coins on mine beep twice, once back, once forth, and are very high pitched. You have to go over your target very slowly, you can gauge how big it is by how many times it beeps. Set your DISC to 0. You will hear more that way. Heck, I don't even use the pinpoint button. It is pretty accurate once you find a target. I plan on making a YouTube video to explain in the coming weeks.
UPDATE-----My wife called me and my cell phone was in my pocket, and as soon as it started to ring, my CZ made funny noises. This could also be a way for interference to come into play.
1. Nails on mine are a mid-tone, solid sounding.
2. Coins almost sound like nails, once you get one, (coin) you will remember that sound.
3. They are almost the same tone, coins are HIGHER!
4. Try the SALT mode, it seems like it is better at judging what the find is.
5. My needle will stay all the way to the right if it is a coin.
6. If the needle bounces all over when you go over it, keep walking.
7. Some older dimes i found bounce between the far right, and the one right next to it.
8. TO VERIFY WHAT IT IS, STAY OVER THE TARGET A SECOND, AND MAKE CONTINUOUSLY SMALLER SWEEPS
9. This will give you a definite answer to what it is in the ground.
10. GROUND BALANCE!!!!!!!!!!