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First, 'Welcome' to the AHRPS Forums. We hope you

October 30, 2016 12:04PM avatar
will frequent here often, both with questions as well as observations and successes you have in your detecting efforts.

Okay, now I'll tackle your post, but excuse me as I do call attention to little things along the way. It's just a bad, or good, habit I have. Most readers likely know what I will mention first if they have followed any of my posts, anywhere, pertaining to some Tesoro model names.

Hi all, I have a Laser Rapier (Tesoro SS Umax) and I've just added an external ground balance control.
Jack Gifford decided his new smaller-size models needed a catchy name, so he used the electronic symbol µ which stands for 'micro' to form µMAX, meaning microMAX, since it is a micro-sized control housing and the detector gives MAXimum performance. It isn't a u or a U, just a µ micro symbol.

I had a Laser Rapier several years ago a fellow in England sent to me here in the USA. At the time he was thinking about modifying one himself to add an external manual GB pot.

I seem to get a good balance in all metal/pinpoint mode but I start getting problems when I turn the Disc' up to about 3/iron
Tesoro had several models early-on where there was a definite design glitch between the Ground Balance and Discrimination adjustment functions. The µMAX Sidewinder (produced from 2/'96 to 5/'98) and the original Conquistador (made from 2/'00 to 2/'01} are two of a few models that shared a common problem. That is, once these preset GB models had been adjusted, if you turned the Discriminate level up or down from where it was set when the internal GB trimmer was adjusted, you would see a shift in the Ground Balance setting as well.

Example, let's say you had the Discriminate control set just above where you would reject a large piece of foil, and you adjusted the internal GB trimmer to be 'spot-on' in the Pinpoint/All Metal Threshold-based function. If you reduced the Discrimination control to the minimum Disc. setting, it would also reduce or adjust to the negative, the GB setting. It could be too negative for the ground you are hunting and cause a lot of noise and falsing.

Worse yet, if you increased the Discrimination to get rid of some higher-conductive junk, let's say adjusted to about the 2 o'clock to 3 o'clock position, you would have also increased the Ground Balance setting, and if it is set too positive, you might not get a response from something like a large silver US dollar or 1 oz. silver round or some other bigger, higher-conductive targets.

If you changed search coils that also caused additional problems because with Tesoro's the search coil is part of the circuitry and it is important to have s proper and efficient Ground Balance.

Tesoro quickly corrected the problem with those two models by coming out with the Conquistador µMAX that didn't have that serious glitch in circuitry design, and the Silver Sabre µMAX (made from 10/'97 to 2/'01) was also supposed to not have that problem and the µMAX Sidewinder would eventually sell out of their inventory.

Now, note that the Silver Sabre µMAX was made before the original Conquistador was introduced and the replacement Conquistador µMAX was introduced in 3/'01, just a month after they quit production of the Silver Sabre µMAX. I was a Tesoro Dealer back when and handled a lot of models. In this past sixteen years I have owned perhaps a half-dozen Silver Sabre microMAX units, have one in my personal arsenal today and recently nabbed a spotless unit for my oldest so who also uses a Nokta CoRe.

I do know that I had one or two early production specimens that had a little 'interaction' between the Ground Balance and Discrimination level adjustments. Once I tweaked the internal GB trimmer so that I didn't have any problems adjusting the Disc. level from minimum to high, and as long as the GB was set so that the detector was 'functional' in all the bad ground environments I search, then I have been comfortable using my Silver Sabre µMAX.

Does the ground balance keep changing the more discrimination I have or does it just shift slightly and stay the same throughout the whole disc range?
I got away from the computer and grabbed one of my very mineralized rocks from my seminar tote, then checked the Disc. and GB functions using my Silver Sabre µMAX, Bandido II µMAX, and an Eldorado (in the µMAX configuration) to see what happened.

I checked the function with the very hot sample rock I use, then went outside to use them over both dirt and other material only to discover the following:

• All of them worked just fine.

• With the manual GB models I set the GB to be as close to spot-on as possible with the Disc. level at minimum, then varied the Discrimination level from minimum (ED-120 accept on the Bandido II µMAX and the ED-180 of the Eldorado shifted it low to all metal accept) up to maximum Discrimination, and there was no discernible change in the Ground Balance setting.

• The preset GB of my Silver Sabre microMAX was just slightly positive on the more favorable ground, close to spot-on in the dirt in my yard and some smaller 'average' rocks, and a little negitive to the intense mineralized rock. However, I have the GB adjusted enough so that I do not get any falsing over most ground mineral challenges. Varying the Disc. control of the ED-120 circuitry from minimum to maximum rejection showed virtually no shift in the GB when I checked in the Threshold-based All Metal/Pinpoint function.

Conclusion: There can only be one of two possible reasons for having problems with the GB setting when adjusting the Discriminate control:

1.. You might happen to have an early production SS µMAX that utilized some of the earlier circuitry from the µMAX Sidewinder or original Conquistador that has the known glitch

-- or --

2.. In doing the modification to add an external manual GB control, you might have done something wrong or crossed up some wiring or other contact somehow.

My Long-Standing Recommendation: When anyone tells me or asks me about modifying a turn-on-and-go model, such as the Silver Sabre µMAX, I always suggest NOT doing any modification. Instead, I suggest buying a Bandido II µMAX, or equivalent European counterpart unit, that was already designed with a 3¾-turn GB pot.

Your unit, now modified, does not work the same as mine, my son's, or those owned by two of my friends as they have already been checked out and compared and work like mine. No abrupt, discernible GB shifting with the Discriminate control use.


"Your EYES ... the only 100% accurate form of Discrimination!"

Stinkwater Wells
Trading Post

Metal Detector Evaluations and Product Reviews
'How-To' help for Coin & Jewelry Hunting, Relic Hunting and Useful Techniques.

My Regular-Use Detector Team are various models from: Makro, Nokta, Tesoro and White's
Pinpointers: Using Nokta and Makro and Uniprobe Pointers.
Headphones: Using Killer B's 'Hornet' and White's Pro Star and Detector Pro's Uniprobe ... All w/'tank style' ear cups.
Recovery Tools: Using White's Ground Hawg Shovel and DigMaster digging tools.
Note: Detectors are listed alphabetically by Brand. Models are chosen as desired based on search site conditions.
Other models on-hand for 'Specialty Use.'
Additional search coils. mounted on spare lower-rods, are on-hand in my Accessory Coil Tote.

*** All working well today to make memories for tomorrow. ***

monte@stinkwaterwells.com .. or .. monte@ahrps.org
(503) 481-8147
Subject Author Views Posted

Silver Sabre Umax GB Shift

LOULAS 607 October 30, 2016 03:09AM

Re: Silver Sabre Umax GB Shift

RickUK 468 October 30, 2016 09:44PM

Re: Silver Sabre Umax GB Shift

Rich (Utah) 351 November 12, 2016 12:34AM

First, 'Welcome' to the AHRPS Forums. We hope you

Monte 638 October 30, 2016 12:04PM

Re: First, 'Welcome' to the AHRPS Forums. We hope you

LOULAS 383 October 31, 2016 05:28AM

LOULAS, back to you.

Monte 441 November 01, 2016 06:35AM

Re: LOULAS, back to you.

WM6 429 November 01, 2016 04:13PM

Re: LOULAS, back to you.

DesertRokon 409 November 01, 2016 11:20AM

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