CZ1280 X Aquanaut DISC settings problems

[sdesic]

I have one Fisher CZ1280 X Aquanaut detector in my hands
and having DISC settings problems...

I set my disc at 0 and detector rejects most iron and even gold rings 14k and 18k...
when I set it to 1,5 it detects all metals....
sensitivity is set to 5 and 9 and both give same result
volume on 5 to max

Coil is 10.5".
Bought used detector ... that is first impression from test inside and outside

is it me or this is normal?

 

[88junior]

I've never heard of a Fisher CZ1280X detector so that's the first not normal thing second it should be able to pick up gold rings if all you have is iron discriminated out so it is the second thing that's not normal.

 

[sdesic]

My mistake not CZ 1280 ... just Fisher 1280 X Aquanaut

 

[Dave J.]

How does the machine respond to zinc pennies?

Does varying the DISC control have any appreciable effect on response to zinc pennies?

 

[sdesic]

Dave,

I will try with a penny in a few hours - I am at work now.
I am in Europe so different time zone also.
Zinc penny is 1983 - now ?

 

[sdesic]

Tried Lincoln penny 1998 at disc 0 and it breaks up
on disc 2 it comes on and stays up to 7
at 7 it breaks up again

volume is at 5
sensitivity 7

 

[sdesic]

Only larger things are found on DISC 0 and made from brass / copper / aluminium
tried amoured concrete and it is found also ... my army entrenching tool also
"small item" as pliers NO...

 

[Dave J.]

Yep,sounds like it's got an ailment. I think I know roughly where in the circuit the problem is. Getting it repaired won't be cheap because of the labor involved in opening up the housing and then closing it up again so it's properly sealed. I don't know whether or not we have a repair facility in Europe authorized to do the scuba rated machines.

 

[sdesic]

It is faulty device then. Sold as a good working one.
I can still hunt with it... tommorow I will try disc from 2 - 4 ... I will not be using 0-1,5 anyway in most cases.

 

[sdesic]

Dave, (and others)

today I went on a test run with 1280 Aquanaut ...
detector was on belt strap
hunted shore of salt lake which I was not able to do with my G2, went OK.
Used DISC 1,5 - 2
SENS 10
pebbles and salt water

good depth

tried edge of water - reduced SENS do 7 ...
It did OK, found some stuff ... coins, pull tabs, nails, foil ...

then I went into lake - up to 25-30cm
on angle 15-30 cm of water
SENS 5
good signals were few coins, bottle tops...
my rubber boot was hollow on 15cm mark and it floded

then I walked out and started on dry pebbles
with DISC 4...
IRON and bottle tops are pops and cracks - breaking up sound

What did I loose with not using DISC 0 - 1,5 ?
Looks like DISC scale just shifted or shrunk to start at 1,5 ...

Please comment.

 

[Dave J.]

Okay, now I'm puzzled. Sounds like you're describing a properly working unit, except for something about what happens or doesn't happen below 1.5 disc.

At zero disc you should detect iron, and as you raise the disc level you should start knocking out iron. Because the electrical phase of iron depends on its shape and at what angle and distance it is relative to the searchcoil, iron will reject over a range (not a definite spot like most coins do) and the sound will be choppy and not necessarily very repeatable. In the range of 0 to about 1, the potentiometer is on the ends of its taper where the pot manufacturer rolls off the slope of the electrical response, so you may not see much happening in the bottom 10% of rotation. (Likewise, you may not see much happening over the range of the top 10% of rotation.)

If for some reason the potentiometer had an electromechanical defect where the wiper was not making contact in the bottom 15% or so of rotation, in that zone things would definitely be screwy. Without a schematic handy I can't say for sure what the result would be. If my memory is correct, however, I think it would be like max discrimination and knock out nickels and probably zinc pennies. Also, if this is the problem its history would likely be that of a developing intermittent and it's possible that the defect had not developed while the seller had it; or, that the seller always used it at a disc setting over 1.5 and was unaware of any problem. In other words, the seller may be innocent of any wrongdoing. ........And, if this is the problem, given the cost of a repair and given that you probably want to knock out iron anyhow, you may be happy with it the way it is.

If that's not the problem, then we're back to square one trying to figure this out.

 

[sdesic]

I was today on a another hunt ... 3 hours with no problems
used DISC 1,75 - 2 and I was digging all - salt lake shore and knee deep (boot deep)
I am not having any issues... few times I did managed to use DISC to find out what is under coil by turning it to 4
and back to 1.5 ... then I lost few iron coins but I did get crackle - disc breaking sound
My country has 5 coins made from iron in sandwich with nickel and copper...
but they read all over scale ... rusted and all
Only two coins are above ID 60 ... something like Euro coin

Don't know it if is mechanical problem as detector was shipped without styrofoam face plate
but I think if it was potentiometer it would be in and out of DISC ...
like bad potentiometer on a radio or headphones

Anyway it is OK to loose some DISC this time ... I am wondering if it will spread to more than 1,5?
Maybe it is logaritmic instead of linear ... I not an engineer here... I build few detectors from parts but that's it

Fisher 1280x box says November 2012 ...

Seller has given 90 days guarantee so he is confident... from Corpus Christi, Tx

 

[Dave J.]

I assumed we were talking about US coins, which are nonmagnetic and fairly predictable. Many nations mint coinage containing magnetic steel, which makes discrimination bounce all over the place even on a single sweep of the searchcoil. Same problem with Canadian coinage, some of which contains magnetic nickel alloy.

At this point with the information you've provided I am unable to tell if anything is actually wrong with the machine.

 

[sdesic]

Thank you Dave, you have been a helping hand.

Coins are from Bosnia and Herzegovina...
Nickel plated Steel, Copper plated Steel and
Bi-Metallic Nickel-brass center in Copper-nickel ring
Bi-Metallic Copper-nickel center in Nickel-brass ring

Next thing I need to do is test in water.
Detector in water for half hour... and then off to feedback on ebay.