Jim in Idaho

Great work, Jason! Jim

I understand, Jeff. I'm curious what the actual voltage was. Also, I wasn't criticizing the test. And I agree air tests don't mean much. But my SL has often targeted a 1 grain gold bar at 3", in the ground. But, I have no experience with Arizona, or Colorado soil. Jim

My only question is why run the TDI at 14.4v? The nominal is 14.8, and the max is 16.8. I'd bet my SL would give a response to that .1 gram nugget, since it gives a response to a 1 grain piece. Granted, it's not a 6000, or Axiom, but it didn't cost me thousands, either. Jim

The newer models, made sometime in 2015 and later, included a modification suggested by Reg Sniff.That mod has been done, by several people, to the earlier machines. It increases the sensitivity. Other than that, they're all the same. Jim

I remember hiking in and staying overnight on Piru Ck. We lived in Simi Valley at the time. I remember my dad talking about the gold there. Hard for me to believe, but that was 65 years ago! Jim

Yup....looks like melted beer bottle glass. Jim

Ilmenite, maybe? Titanium iron oxide. Not sure if ilmenite is magnetic. Jim

Yessir...,that is REALLY cold doins, for sure. Worst I saw was a job at Crested Butte Colorado in '73. -44 every single morning for 10 weeks. But super arid, and with the high elevation (10,800') sun, not that bad. Wind is a super-killer. Back in Feb of '89 we had -40 and 40mph wind for several days. Windchill at -90. Killed everything that couldn't find shelter from the wind....elk deer, antelope (lost 80% of the state herd), coyotes, cattle, sheep. Same happened in '48- '49, but I wasn't here then...LOL. Easy to look back on, from a warm house, but not funny at the time. John, up there in Edmonton, puts up with extreme temps a big part of the time. Don't know how he does it...Ha!, but he's got my respect. Jim

Yup, Chuck. I remember, back in my fur-hunting days, mid December, sleeping in the divide basin in Wyoming at 7,000', in the open bed of my little Chevy LUV 4x4. One bag inside another, and my Air Force arctic parka over the whole thing. Not a human within 40 miles. Worst part was getting up in the pre-dawn at -20 degrees, and praying the truck would start. ..................................best days of my entire outdoor career....LOL Jim

John, I'd take a good look around, at the area, for future reference. Get a good idea in your head about why that patch is where it is. Might lead you to more of them. Great job in any case.👍 Jim

LOL....what are friends for, if they can't help? Jim

Yup....gettin' old is not for sissies, for sure. I'm approaching 75, and this has been one of those seasons where I feel like I did a big leap downward. Still hiking uphill at 8,000', but I'm feeling it more, and the legs just don't have the power they did a few years ago. I'm really happy with your progress. Not everybody heals as well as you have. Keep it up! Jim

Yup, Gary, it's like "Back to the Future"....LOL. Hope you're doin' good buddy! Jim

I really appreciate the great pics, Pat! Nice work. I'm also eagerly looking forward to field reports...even birdshot finds and depths...LOL. Jim

IMHO, a person should move with caution on any mod not suggested by either Reg Sniff, or Karl. I doubt a 10% increase in gain would be noticeable in the field. Some mods are all about the risk/reward ratio. Same goes for boosting the voltage...at some point you're risking the health of your machine for very little increase in depth/sensitivity. Boots on the ground, and geologic self-training on where to detect would make a bigger difference. Jim

I had no negative effects from doing the SS mod. Looks like you did a good job on the switch. Wish I had time to do that mod on mine. With the dry sluice project, and the resistivity, I'm buried in projects...LOL. Having a LOT of fun with the resistivity, though it's fairly boring setting up and collecting all the data. Best of luck on the gold, Pat. Looking forward to tests and results. Jim

Karl, I'm curious about what controls U7d? Thanks. Jim

Thanks, Pat, but don't confuse my tiny bit of knowledge with Karl's far great ability. Compared to him, I'm a hack with a small bit of experience with one particular detector. We're very fortunate to have him to explain all this to us, and I, for one, am grateful. Jim

I appreciate that info, Karl! I had thought it required some serious surgery to change the timing. Definitely more than I want to tackle. Jim

resistor can go on either side of the switch, Pat. Solder one resistor lead to switch, and the other to one of the wires. The resistor is in series with the switch. So TP2, resistor, switch, TP31. OR, TP31, resistor, switch, TP2. Doesn't matter. Jim

As far as I understand, the delay on the SL can't be lowered below 10 microseconds. The timing circuit is fixed. Jim

No, Pat...the resistor has to be switched into and out of the circuit. So, when the switch is "on" the resistor covers the cap. When the switch is "off" the circuit goes back to the factory setup. In effect your changing the circuit from not allowing DC current through the cap, to allowing it past the cap via the 1k resistor. Jim

You want the resistor to be across the cap when the switch is "on". Don't fool with the cap. As Karl said...without the resistor in series with the switch the output of the opamp would be directly shorted to ground.....not good...LOL. I'm looking forward to some comparison tests with the switch on and off. Jim

I have no idea on the switch. I'll definitely install one when I do this mod. As far as the test point location, I was more interested in where TP2 was in the schematic, but appreciate the pic in any case. Jim

Many thanks for the explanation and schematic Karl. I think the mod called for a jumper from test point 31 to test point 2? I'm not sure where TP 2 would be. Jim