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A few CZ-20/21 questions, and one observation.
Posted by: Greg (E.Tn)
Date: October 20, 2016 06:06PM
I have two CZ's: an upgraded 21, and a CZ 20 I bought cheap for a backup.

First question: Is there any reason to upgrade the 20 so long as it is working OK? It is in really good shape and watertight, pinpoint works great, though I don't use it so as to not wear out the rubber membrane. The only reason I can see for upgrading it would be sort of like "preventive maintenance."

Second question: Does anyone know if Fisher (or anyone else) can adjust or modify the salt discrimination to make the CZ-20/21 more sensitive to small gold?

Is there anyone out there who tweaks CZ's to make them more sensitive to gold, and if so, can they modify a underwater detector without compromising the waterproof integrity of the housing?

Now for the observations:

During one of my last water hunting outings, I was detecting a river where tubers frequent, and have been lucky enough to find the occasional ring here and there. The bottom of the river consists of piles of boulders, and there are areas where the boulders are piled a foot or two deep, so that any coins or rings that make their way to the underside of the boulders are likely beyond the detection range of the machine. Once they make it to the actual river bottom, then they work their way even deeper.

So, I started investigating targets that sounded like they might be at the extreme detection range of the machine, especially low iron signals that occasionally bounced to a medium or high tone. Instead of routinely ignoring the iron "grunts" and moving on, I instead worked them a bit more in an attempt to tease a medium or high tone from what might be a good, deep target that is giving off an iron default tone, though it is actually non ferrous.

Also, I moved a lot of rocks so that I could get the coil closer to the actual river bottom.

Two of the bouncy signals, that were mostly low tones but had an occasional bounce to low or high tone, turned out to be rings, once I was able to get the coil a little closer to them.

I've noted that many detectors discrimination capabilities start to erode at certain depths, depending on the machine itself, and the default reading/tone is iron. I was suspecting that some of those iron grunts were good, but deep targets that the machine read as iron.

So, it might pay to investigate some of those iron grunts in some of your old honey holes, especially ones that were productive but now finds are few and far between.



Re: A few CZ-20/21 questions, and one observation.
Posted by: Dan-Pa.
Date: October 22, 2016 10:04AM
Cost prohibitive to change to CZ21....really high price to be done by Fisher. Leave well enough alone.

Take one apart and better have new set of rubbers or indeed it will leak...

Thanks Dan.
Posted by: Greg (E.Tn)
Date: October 22, 2016 10:27AM
I'll probably just leave them alone then.

Re: A few CZ-20/21 questions, and one observation.
Posted by: scubadetector
Date: October 22, 2016 12:27PM
If not broken don't fix. IMHO I think the CZ-20 is better than the CZ-21. I have had both for a very long time. Nobody will tweak them better.

I THINK the new parts for the CZ-21 are made in China. But nobody will say yea or nay.

The cost to make a CZ-20 into a CZ-21 is 300.00 and that is including shipping back to you. IF it needs new headphones or a new coil add 60.00 for the headphones and 149.00 for a coil.

I would NEVER use the pinpoint on a CZ-20. In fact, I had First Texas disable the button on the CZ-21. I am spot on just seeing where it beeps and can dig accurately.

Re: A few CZ-20/21 questions, and one observation.
Posted by: tvr
Date: October 22, 2016 03:00PM
Here is a link to a post by The Authority on the CZ to essentially the same question about upgrading a CZ20:,2299119,2299152#msg-2299152

Thanks tvr and Scubadetector
Posted by: Greg (E.Tn)
Date: October 22, 2016 09:43PM
I am going to leave it as is.

Again, thanks for the very excellent advice.

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