Latest TDI SL mod..

[Jim in Idaho]

I've always had trouble getting the GB and Threshold exactly right on my TDI SL. After seeing Karelian's thread on the vernier knob, I decided to see what I could come up with. The problem with the control the guy suggested to him was that it had limited movement. Ideally, you want the vernier to turn as many turns as need to move the potentiometer through it's full range of travel. After hours of searching I found what I needed. A solid brass and stainless vernier with a 1:6 ratio. One full turn moves the GB pot about 1 1/2 numbers. I can now easily get the GB to that "just quiet" point, and it stays put. No more tree branches, or coat sleeves inadvertently moving the controls. I can easily set the Threshold to the very edge of my hearing, and as the batteries discharge and the Threshold creeps up, I can make a tiny adjustment and it's back on the money. As far as immediate and stark difference, this is the best mod I've done. It took me several hours to machine the bases, but the way I made it requires no physical mods to the machine. Remove the pot nuts, put the base on and replace the nut. I had to make shims for the pot shafts, as the verniers are made to fit a 1/4" shaft, and the shafts on the pots Whites used are .234". Had to make some very thin-walled round shims to glue inside the vernier sockets. I'm planning on selling these kits fort $150 for both controls, or $75 for a single. If anybody is interested, you can PM me here.
Jim

Now I'm really looking forward to our Nevada trip in June! My SL is about as good as an SL will ever be. It's going to be interesting.

 

[Diggindumbstuff]

Very nice! I sure wish I had those kinda smarts. Congrats I hope it serves you well!

 

[Jessgo33]

How dose that work? I have to say those look really cool.

 

[Jim in Idaho]

Jess, they're gear reduction controls. They turn 6 turns for every turn of the detector control. You have to mount them on a fixed base so the bodies don't rotate. They are fastened to the detector controls by a set screw. I machine the bases from a solid block of aluminum, and fasten the standoffs to the bases. Pretty simple to install. The two big copper nuggets I found in Nevada last week were deep and really weak signals. Not sure I would have detected either one without having that Threshold really faint, so I could hear the the targets just break the Threshold.
Jim

 

[Jessgo33]

What do you charge for that? And do you get more control of the detector? I wonder what is the benefit of getting the set up.

 

[Jim in Idaho]

I charge $150 for the pair, shipped. For me the benefit is being able to very accurately set the Threshold and Ground Balance. IMHO, that's a big help when looking for small targets. For guys using it for the beach and relic hunting, it's probably not worth it.
Jim

 

[Jessgo33]

My machine works so well stock. I have no problem working in the highest mineralized ground. That would be so much better. A half number is all you need to gb in some cases. You got some really good smarts to modify it. I got a warranty on mine and dont want to mess it up yet. I will be in touch Jim.

 

[Jessgo33]

I charge $150 for the pair, shipped. For me the benefit is being able to very accurately set the Threshold and Ground Balance. IMHO, that's a big help when looking for small targets. For guys using it for the beach and relic hunting, it's probably not worth it.
Jim

Jim let me know when you get back. I want to know if I can have you do the controls and a battery for my whites TDI SI. Thanks

 

[Sven]

I use these on my Pi's. The red box was I made special for my friend in Oz.