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Looking For Whites TDI Mod Info


Glithium

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Better picts looks like a resistor and a couple of diodes n some wire wrap type wires used a jumpers. Hard for me to see color code on resistor n numbers on diode, but then again my eyes have been getting worse need a magnifier for that. Hopefully when Carl sees it he knows what values they might be of components.  It looks like a simple mod.  I wonder if the diodes in there are to stabilize the current in that circuit mod.  Interesting.  Of course it could be 2 resistors and a diode for a regulator.  Tough one not being able to see under the magnifier.  All bear with me I have chemo brain and it’s tough sometimes for me to write stuff down — darn Side effects.  My grammar and chain of thought stinks sometimes.  Thanks for picts I’ll keep thinking it..

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That's terrific Snake Jim sending off your modded TDI to Carl, he's probably the most qualified we have around for future TDI advancements.

Based from reviewing notes, reading TDI Mods related threads and opening up my TDI this morning for a look.  Unfortunately, Forgot a lot from my conversations with Reg on the TDI Mods. What I will share, is what I remember and it's not much. 

First, Rick Kempf sold me his modded TDI. Over the years have purchased several great deals from Rick. Great individual, very fortunate he passed the TDI to me. 

Soon afterwards, On a phone conversations with Reg, he mentioned the changes on the TDI and that he was having a friend do the mods for him. Later, Noticing two mods where missing, I called Reg back and unknown to him these mods had not been completed. Apparently, his friend had not added these additional mods. However, it may be due to location as some areas these two additional mods are not needed.  That was both Reg and myself feeling on the matter, no harm done Regs friend made that decision as he probably felt certain areas didn't need these additional mods.

Later, Reg sent me the two needed capacitors to replace the original two and instructed me how to perform the third mod. 

Capacitors C59 & C60 need to be replaced with 104J/RS. I believe this was to bring regular TDI filtering up to speed with Pro model.  Please don't quote me on this, but I think that was the reasoning for replacing these two capacitors.

And capacitor C50 needs to be grounded, However, I'll need to double check this as I believe it was capacitor C50.  Please no one ground this capacitor until I double check it. Grounding this capacitor eliminates a filter in which increases Gain. With this, user can reduce gain 15-20 percent bringing gain back to normal when needed.  What I did, was add a switch in which turns off the modded gain with a flip of a switch. 

Regs mod is a work of art, and afterwards calibrated to ensure mod is working peek performance. The PCB trace mod is labor intense, $125.00 was a steal. Regs friend was very professional, very skilled. We were very fortunate Reg had a friend do his mods for him towards the end, we all know Reg towards the end couldn't solder with a steady hand and I believe his vision had given in as well. 

Will enclose a few pictures of my opened TDI, I did add in an inline PI probe with a switch between both coil connectors. The added switch on top with the added Gain switch for the Gain mod, no need to add a switch just grounding the capacitor is enough.

My apologies for rambling on so long, hope the pics show 

Paul (CA)1303387552_IMG_20221201_1108374.thumb.jpg.6d5c1fff2d4f820ed7f18e7e30665618.jpg1220813684_IMG_20221201_1115055.thumb.jpg.d19ea72dd3df43458290a9c970c6171e.jpg879276057_IMG_20221201_1134192.thumb.jpg.ad480086518f7cbd2f8209c4f32b5198.jpg

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Paul — all this helps.  Nice to get this documented.  Wish I would have had a chance to meet and talk to Reg.

Jim — also thank you for sending your machine off to help everyone.

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C59 & C60 need to match each other in value to 1% or less. Otherwise GB will be noisy. Reg was shorting C50 which does eliminate a high-pass filter stage. I've never tried it but see no downside to doing it.

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Thanks Pi-Man,

 

If I come across more information, will share.

Definitely, I wish you and others had the opportunity having a phone conversations or two over the phone with Reg.  Truly, A remarkable individual. I enjoyed the many conversations with Reg, not only metal detecting related but also involvement with helping his employers succeed with Regs equipment modifications. 

Good luck, enjoy and have an adventurous journey scraping coil the soil.

Paul

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On 11/30/2022 at 1:12 PM, snakejim said:

A Reg Modified TDI

 

 

100_0390[1].JPG

100_0393.JPG

100_0395.JPG

Thank you that yellow circuit board must be the key I can't really make it out but with these picks a little asking around on the right forums should do the trick.

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On 12/1/2022 at 11:40 AM, PI-Man said:

Better picts looks like a resistor and a couple of diodes n some wire wrap type wires used a jumpers. Hard for me to see color code on resistor n numbers on diode, but then again my eyes have been getting worse need a magnifier for that. Hopefully when Carl sees it he knows what values they might be of components.  It looks like a simple mod.  I wonder if the diodes in there are to stabilize the current in that circuit mod.  Interesting.  Of course it could be 2 resistors and a diode for a regulator.  Tough one not being able to see under the magnifier.  All bear with me I have chemo brain and it’s tough sometimes for me to write stuff down — darn Side effects.  My grammar and chain of thought stinks sometimes.  Thanks for picts I’ll keep thinking it..

I posted it on Geotech just to see if anyone else has an idea.

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