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  • Location:
    Denver, CO
  • Gear Used:
    DFX w/ D2 coil - NiMH battery conversion. TDI SL Special Edition w/ various coils.

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  1. In one of the french forums... someone posted this... with a threshold bump protector.
  2. Thanks Geotech! Thanks some great information, especially from someone who worked on this specific product. Here is a photo of the PCB (thanks to pjrough) - with the capacitor locations as Geotech pointed out.
  3. Jim: Thanks for the info! My machine is the SL special edition (tan box), with the later High-Q coil. I assume I'm covered with both the mods you have mentioned. Geotech: Thanks for the input! Having scoured the 'internets' it seems many of the threads mention to not exceed 16V on the SL version. That is definitely good news! I have been undercharging my Li-On batteries to about 14.8V. Sounds like we have plenty of headroom to bump that a bit. I remember having looked up the components, and they didn't quite match what other were saying in the forums. I think the caps are panasonic (1000 E FK) 1000uF, E=25V and FK series. Voltage regulators look like Fairchild FQT7N10 - but I could be completely wrong. All I remember is that the voltage specs didn't quite match up to what I found on mouser/digi-key.
  4. Cascade: Here's the link, hopefully I'm not breaking any rules posting cross-threads from other forums. I use Google Chrome's (right-click) translate to english to convert the text. https://www.forum-sud-prospecteurs.com/t7997-Adaptation-TDI-SL.htm Definitely a lot of info posted in our forums - just don't recall some of the specific ones being mentioned in the above link. Maybe I haven't looked hard enough. I remember hearing about the sweep speed mod, and the battery pack. edit: one more thread about lowering the pulse delay below 10uS. I believe it was discussed in our forums, or sending it off to Reg to perform the mod. However, this individual shows where/how he performed the work on the PCB, specifically for the SL version. https://www.forum-sud-prospecteurs.com/t9026-White-s-TDI-au-dessous-de-10us.htm
  5. I came across a french prospecting website where some interesting mods had been done to their White's TDI SLs.... for instance: 1. Removal of resistor R86 within the gain circuit - providing a boost to the gain control. They believe this was to make it stable, for less complaints. Removal of this resistor provided additional gain reserve. They had some good results with their testing. 2. Placing thick o-rings under some of the pot knobs. Helps to add some friction and avoid dials turning themselves accidentally, especially with the above modification. 3. With a single +16V battery pack, there was feedback that depth seemed to increase on the TDI SL. However, this came at a cost of over-driving the 16V rated power capacitors as well as other circuits on the board. Potentially shortening their life, by running them full time. The moderator seems to have been able to add another battery pack in series (6V) with the 12V pack, and use a toggle switch to drive the voltage above 18V temporarily. This "boost mode" was done as a method of improving a faint signal on-the-fly. Just a flick of a switch, double-check that faint signal, and then back off. Ultimately, it seems they were discussing driving the coil with it's own 18V external battery and using the standard 12V battery pack to drive the rest of the board (logic). Basically driving the pulses in the coil without going through the voltage regulator, via a large MOSFET. Unsure if they actually were able to do this mod. Anyways, just thought they were some interesting ideas those french detectorists were messing with.
  6. I thought maybe the MJ coil and this coil were similar in dimensions... but if I'm reading the forum correctly. The MJ coil is 8x12 and the High-Q coil is 7.5x12. So I suspect any coil covers would be different. Or is it better just to make one?
  7. Curious if Sun Ray or another 3rd party vendor made an inline probe for the TDI? Thanks in advance! Gabe
  8. The Whites SPP is similar, if not, the same machine but missing the delay knob. I came across a post in this forum that described the PCB board being the same. If you search for "whites spp metal detector" on youtube - you'll come across some in-field reviews of the SPP version in Australia. Unless you're asking specifically about the Hi-Q coil itself?
  9. Hello everyone! I'm new to the forum and have been an on-again, off-again DFX user for the last ten years (family, kids, work, life, yada yada yada). I picked up a used TDI SL special edition. Figured since we moved to Colorado back in 2014 - why not? I had always wanted one and this one came with a few coils and a Li-Ion converted pack. I wanted to ask - I went out to the backyard to give it a run through. Found a few nails scattered through the yard. However, I noticed I could not use any type of ground balance, as the machine would start to 'pulse' in my ear and sometimes increase in intensity like a feedback loop. If I completely turned off ground balance, it wasn't an issue. I came to find out that the closer I was to my service panel, it would increase. This would make sense since the power lines most likely pass underground through my backyard. My question is: are there any concerns with damaging the front-end receiver on the TDI SL? It was rather alarming when I flipped on ground balance. Thanks in advance! Gabe
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