CZ-20 Ground Balance Question

My CZ-20 arrived today. According to the paperwork the unit was bought in 1996 and I am the second owner. I took it out to my test garden and ground balanced it using both methods described in the manual, pretty straight forward stuff. I'm surrounded by the wonderful Tennessee red clay. In my yard both my F75s ground balance(d) around 66, my CZ-3D comes in around 6.5 or so. The CZ-20 however, with the Sens. at 8-10 balances at 8.5-9. Since the scale stops at 10 and considering where the other detectors ground balance, it seems a little high to me and has me concerned that there might be some places that the detector just won't ground balance.

Does this sound kosher to you guys? Also, are these units prone to drift over time and if so, can they be re-calibrated?
Having just bought it used I just want to be as sure as possible that everything is okay.

Thanks,
Chris

Chris,

The CZ-20 is locked in 'salt' mode..........and will make this difference. This is not a problem. Did you get the 8" or 10.5" coil?

Thanks Tom, I got the 8" coil but as I posted previously I am giving serious consideration to splicing the coil wire with a waterproof connector in order to gain the ability to add the 5 and 10.5 inch coils to the detector in the future.

Is it at all feasible to get into the detector and add a "mode" switch that will enable it to run in the normal mode available on other CZs? I was thinking that there might be room in the battery compartment for a micro switch but do not know if the detectors electronics would support this.

No......not on the CZ-20's and 21's.

If you water proof the connection, would it be at the machine side or the coil side, and where would you get the coils

Getting the coils is easy. Any CZ coil with work on a CZ-20. I did that already. The waterproof connection would need to be waterproof on BOTH sides