coil problems

[jhamner]

Someone PLEASE help! I've been a White's user for over forty-five years and I LOVE my MXT's.
My problem is with the coils--I mainly use a White's Eclipse DD coil, but in anywhere from two weeks to several months, they start chattering and sounding off, even when I hold them up in the air.This last one has started screaming at me and displaying the overload signal as soon as I turn it on. Before it started screaming, it would sound off every time I swept it along the ground, but there were no targets!
I can't tell you how many times this has happened with a DD coil, as well as the Shooter coil and the big 300LTD. I hunt with the dual control just below preset (around 3) and the gain wide open.
There hasn't been an MXT coil that I have owned that hasn't been back to White's AT LEAST once, but often multiple times. Those folks at White's are SUPER, fixing my coil every tine and at little or no charge, but now I am literally too embarrassed to return the two I have "on the blink."
Can anyone out there tell me what I'm doing wrong?--I don't blame Whte's in the least for my problems. I try to be very careful with my machines--control moisture, direct sunlight, etc. and try never to strike the coil against any hard object such as a rock or a tree.
If anyone has any ideas, I would LOVE to hear from you--cooler digging times are quickly approaching, and I have two "sick" DD coils--don't know WHAT to do! Thanks! Jack.

 

[Aarong81]

Three things come to mind to try but it may not be any of them.

First, I have a similar problem when my batteries are getting low but not low enough to show 'low bat'. The MXT becomes really chattery around 9 volts and fresh batteries always clears that up for me. But I doubt it as as simple as that in your case.........

Second, You mentioned you run your gain wide open and that can cause on overload signal with even minor ground minerals. If your having any noise/chatter/overload issue you really need to sacrifice some gain to get rid of some noise. Too much gain is often detrimental and really common for users to set it too high.

Third, From your experiences with the coils you have mentioned it sounds like they have all started out ok but quickly became noisy and even giving overload signals, correct? This behaviour is consistant with the coil cover getting dirt, sand or ground minerals in it. It doesn't take very much in the coil cover to cause these issues.

These are all really simple issues to fix so I hope one of them helps, but there is one other less simple problem I can think of as well......

Awhile back I was looking into buying an SEF DD coil for my MXT and I did alot of reviewing and decided against it because the reports were inconsistant and some users complained that they de-tuned their machine. It scared me out of buying one but the symptoms may match what your experiencing.

Does your MXT still act ok if you put a brand new coil on it, if only for awhile at least? And have you tried putting one of your problem coils on another MXT to see if it acts any different than with yours?

 

[Larry (IL)]

Out of all of the great suggestion made by Aaron, I would suggest trying the battery replacement when the MXT gets noisy next time. If you have had many coils and the problem still exists, I would guess the problem is in the unit and low batteries would be enemy #1.

 

[widebody]

[size=large]going along with larrys thought i would get some electrical cleaner spray and wash the cicuits. remove the battery holder and spray and and let it wash out the box. there are some brands that don't leave residue.

HH[/size]

 

[jhamner]

Three things come to mind to try but it may not be any of them.

First, I have a similar problem when my batteries are getting low but not low enough to show 'low bat'. The MXT becomes really chattery around 9 volts and fresh batteries always clears that up for me. But I doubt it as as simple as that in your case.........

Second, You mentioned you run your gain wide open and that can cause on overload signal with even minor ground minerals. If your having any noise/chatter/overload issue you really need to sacrifice some gain to get rid of some noise. Too much gain is often detrimental and really common for users to set it too high.

Third, From your experiences with the coils you have mentioned it sounds like they have all started out ok but quickly became noisy and even giving overload signals, correct? This behaviour is consistant with the coil cover getting dirt, sand or ground minerals in it. It doesn't take very much in the coil cover to cause these issues.

These are all really simple issues to fix so I hope one of them helps, but there is one other less simple problem I can think of as well......

Awhile back I was looking into buying an SEF DD coil for my MXT and I did alot of reviewing and decided against it because the reports were inconsistant and some users complained that they de-tuned their machine. It scared me out of buying one but the symptoms may match what your experiencing.

Does your MXT still act ok if you put a brand new coil on it, if only for awhile at least? And have you tried putting one of your problem coils on another MXT to see if it acts any different than with yours?

Thanks so much, Aarong81 and sorry for the delay.......our computer has been on the blink. Yes, the machine works perfectly with a new coil--it's only after lots of use that it starts acting up. Where I live the soil allows me to crank the gain up all the way, so that's usually what I do (wondering if this is hard on the coil?) Most new coils last for several outings--up to maybe 50 hours or so before they start false beeping, even when the coil is held at waist height. The noise usually gets worse if I swing it side to side in this waist high position. I've tried a different coil and it works fine. I replace batteries about every 12 hours or so. They still read "11" on the display, and I guess this is wasteful, but I like to keep them fresh. I removed the coil cover and thoroughly washed it and the coil, and retried, but with the same results--a screaming "overload" as soon as I turned on the gain button. (I have a second coil which I cleaned, but this one just constantly "false reads") Don't know what I'm doing wrong! Thanks again!

 

[jhamner]

Out of all of the great suggestion made by Aaron, I would suggest trying the battery replacement when the MXT gets noisy next time. If you have had many coils and the problem still exists, I would guess the problem is in the unit and low batteries would be enemy #1.

Thanks Larry( IL)--I always replace my batteries after about 12-15 hours of use, even if the screen reads then as "11" (I recycle them) I guess this is overkill, but I always like to make sure they are fresh.

I'm pretty sure the problem is in the coil itself--a different one works fine, and cleaning under the cover and cleaning the coil doesn't help. It sounds as though something has "worked loose" in the coil itself, and I know of no way to get inside to see for myself without doing more damage. As mentioned before, the GREAT folks at White's have always repaired my coil at no cost or sent me a new one, but I just cannot ask them to do that again! They have helped me already about 5 or 6 times within a time period of just a few years!

 

[jhamner]

[size=large]going along with larrys thought i would get some electrical cleaner spray and wash the cicuits. remove the battery holder and spray and and let it wash out the box. there are some brands that don't leave residue.

HH[/size]

Thanks, widebody! This is one thing I haven't tried, although when I try a new or different coil, it works fine, which leads me to believe the problem is in the coil itself. Nevertheless, I will be sure and try your suggestion. Thanks! Jack.

 

[HuntinDog]

One way to tell if it is the coil for sure would be to put the coil on another machine and see if it does the same thing.
Did you try lowering the sensitivity and seeing if it still does it??
I can't give you any good suggestions except send them into Whites.
If there bad there bad.
Whites will take care of you.

HH

 

[Tom Slick]

Maybe you're winding the coil cable too tight on the rod and not leaving the cable loose enough for relief as the coil gets moved up & down in relation to the rod. Cables won't take much pulling on them before the coil goes bad. Just a thought.

 

[Aarong81]

I have a DX-1 pinpointer that has a break in the wiring going in the probe from so much usage and flexing and I contacted Sunray about it and they had me explain the symptoms which were pretty much exactly what your experiencing. It would seem fine 1 second and then BLAM 'overload'. They told me that the overload gave away what the problem was, it was a short in the wiring inside the cable. I didn't want to send it in for repair so I disected it myself and sure enough the cable protector right at the probe has a tightning nut that grips the cable and has sharp points to "grip" the cable which were cutting directly through the insulation of the wiring. So I loosened it and slid the cable further into the probe and placed a bit of rubber under the sharp points and re-tightened the cable gaurd nut and now its good as new again.

I didn't think to compare that problem with yours till now but it may just be a short in the wiring like Tom Slick pointed out.

 

[CoolTex]

Might want to send the unit and coil in to Whites for a check of the whole unit...they priced an evaluation for mine at $50 plus parts. Call them for a price...It'll be home in a week or so...

 

[jhamner]

MANY,MANY thanks to all who have been trying to help me! Our computer is one of those that "crashed", so I'm using a friend's just to send a quick note. I will try and answer you all when we're back up and running, but heaven only knows when that will be! Thanks again for ALL your help!!! Jack.