I bought my Silver uMax (new) in early 2012, so I don't know how different
the electronics, software, or coil are from your 12-year-old one. With that
disclaimer, here's what I've noticed with mine (related to your situation):
1. I definitely get interference sometimes in certain areas. The areas seem
to be near power lines or power sources. There's a chance that's it's really
wifi devices or something else, but it seems to be power to me. This includes
the power lines that run from the power poles down to my house (and my
neighbors). I've also seen the problem when I was close to certain lighting
fixtures (not all, maybe just certain fluorescent ones?) and when close to
big electronic motors and/or transformers. However, you should be able
to confirm whether this is your problem by simply moving around while
running your detector. Once you're 50 or 100 feet from the possible
source of the interference, the noise should go away. If you keep hearing
the noises when you're, say, out in the middle of a park or a beach with
no wiring anywhere near, the cause is something else.
By the way, this problem is strongest when you operate in All Metal mode.
In Discriminate mode, you can reduce or eliminate the noise by lowering your
Sensitivity setting.
2. I once had a problem with a bad coil on my Silver uMax. It was the original
eight-inch concentric coil that came with it. The noises it caused sounded
like Morse code, but it was more random. If I shook or tapped the coil gently,
I could often get the noises to stop. Then, after swinging it normally for a
while (sometimes a few seconds, sometimes many minutes), the Morse code
would come back. I finally sent it to Tesoro and explained to them how
to reproduce the problem, and they replaced the coil (for free, except I had
to pay shipping one way to return the coil). With the new coil, it's fine. The
problem has not come back.
So, If you have access to another coil that works with the uMax, try the
other coil. If the problem goes away, the coil was obviously the problem.
(Of course, the problem might not be the coil itself. It might be the cable
or the cable connector, but that's all part of the coil assembly in my mind.)
Maybe there's a detecting club near you or another user you can find on
the forums, from whom you can borrow a coil for a test.
If you have any interest in the 11-inch DD widescan coil for your uMax
(which lists for $100 and sells for about $85), you could buy that (or borrow
one) and see if the problem continues with it. I bought one and really like it,
although it's more tiring on the arm and shoulder because it's heavier.
Also, I had my uMax "retuned" at the Tesoro factory (for free, except shipping
one way) because I told them I planned to use the 11-inch almost exclusively
from now on. The uMax was certainly usable with the 11-inch without the
retuning, but you might get more chirping if the ground you detect is mineralized
enough. The retuning process involves Tesoro reducing the fixed ground
balance level to eliminate this excess chirping.
Just a few thoughts to consider. Let us know how it all turns our for you.
You could also just phone Tesoro and ask to speak to Rusty Henry or one
of their repair technicians to see what they suspect your problem is. They
certainly know much more about what might go wrong with a Silver uMax,
especially one that's at least 12 years old.
--Tom
