Ouestion on Batteries

[NLINE SIXX]

I was fooling around with the MD this afternoon in the yard and was operating the machine in coin mode. I kept getting a belltone signal and reading of a coin (quarter) about a inch away from the slab foundation showing a depth of 5 inches deep. So I dig down at least 6 inches never finding any coin or trash or anything with a fairly wide hole before it's over with and also checking the dirt I dug out of the hole for the goody. So I finally gave up trying to locate the coin and moved on, then all of a sudden my needle indicator stuck (I have a Garrett Grand Master Hunter CX II with a analog type display) so I turn off the MD and turn it back on again and needle indicator is still stuck toward the center. Now I'm thinking possibly the batteries are weak, but can't check them since indicator is stuck, so I go inside remove the batteries which it holds 6 C size and four them check out around 80% to the good and two of them show to be pretty much dead. My question is would real weak batteries give me a false signal indicating there's a coin there when it's not and will new batteries installed un-stick the meter because even with the batteries removed the needle indicator is still stuck about the center. I'm still pretty much a newbie at MD, I'll have too make a trip to Walmart tomorrow for a new set of batteries.

 

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[NLINE SIXX]

Well the new batteries did un-stick the needle ok so that was a relief. When they went dead it was all at once so keeping new spare sets on hand is a must. Took it out after the new batteries were installed and found a few coins in the yard.

NL6

 

[dirtyknees]

When you say slab foundation, this is concrete right? If it is you may be picking up a signal from the rebar in the concrete. I just started MD this past year myself and spent most of my time at the beach. They used concrete as part of the breakwall I was MD. The concrete was under the sand so I dug a little ways down before I figured out what I was digging up.

The battery situation I have come across too. Unreactive meter, loud screaming noises needle going nuts. Change batteries and everything is Ok. Strange.

Good luck, Dave

 

[Sandman]

Yes, Garrett machines will do this sometimes, weak batteries or not. I once had to send my ADS-7 to unstick the needle.

If you are using rechargable batteries, when they die, they just stop without telling you they are low. Regular alkila batteries run down slower. Not to big a problem if land hunting, but for water it's a bummer. Rebars in the concrete will give signals like this or junk under the concrete. I once dug down eight inches with an older detector to find a sewer pipe set at an angle.

HH,
Sandman

 

[NLINE SIXX]

Thanks guys for the reply and "yes" to it being a concrete foundation aka "slab". This morning I returned to my yard to locate what I thought to be another coin about 2 inches deep I came across yesterday, but it was getting dark at the time. Turns out to be a old flat top nail used to secure felt on the roof decking before the shingles are put on. I had the indication of a quarter on the meter along with the belltone of a coin. I was kinda surprised to see that nail instead of the coin. It had the same tone as the other coins I've found. I have run the MD over rebar, other iron objects, wire, etc, and just either get a faint tone or nothing at all in Disc mode pretty much indicating trash or iron. A nickel or pulltab shows the same on the meter either points to nickel or pulltab and same tone so 50 50 chance its a nickel or pulltab . So far all the other coins seem to be dead on if I hear the belltone and if it's indicating a penny, dime, quarter that usually is what I find. I'm still a novice at this and maybe not interpreting the meter all that well but hopfully experience and time will pay off. I have been doing lots of reading on this forum and theres lots of good info.

NL6

 

[Monty]

If you can find a smaller coil something like the Garrett Stinger, it will cut out most of the interference from the rebars. Works good along fences too. Last summer I chased the edge a concrete walkway/ bike path that had rebars across a "hunted out" park. I used my BH Landranger with a 4 1/2" coil and found several dollars worth of clad and a few wheats that had been missed by many hunters with standard coils. Did the same thing right along the edge of the basketball court and the fence of the backstop of a ball park. If you like to coin shoot, the small coil is a must! Monty

 

[NLINE SIXX]

A little update on the new batteries installed, well they did not solve the problem of the meter needle sticking like I thought. So I email Garrett for a solution. I received a reply the next day telling me to try cleaning the internal face plate with windex, explaining that over time the fine particles of dust can cause the needle to act erratic at times. I did this using q-tips lightly sprayed with windex and then used a dry q-tip as a follow up. It helped a lot, but I did notice my last time out detecting the needle did momentarily peg out a couple times, so maybe I did not get all the dust like I thought. Anyway if your having similar problems you might try this first before sending it off for service.

NL6