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Hi I'm looking to see if anyone still mods TDIs I have a original big box model I was wondering if I could get some instruction links so I could do it myself becuse it's probably hard to find someone that mods them now a day.

Hi, so... i bought a secondhand whites spp, i'm still waiting for it to arrive at my house. i was looking to buy a extra coil. i have got a xp deus 2, and i'm looking for a deeper detector, the dream was minelab gpx, but too expensive... I read some reviews of this machine, and it seemed like a good choice. i'm from europe, so almost every coil that I read were good, I just can't find them here in Europe. i have two options, or a minelab coil, or a detech coil. i was looking at the detech coils, and i found this "DETECH 18" MONOLOOP CLOSED DESIGN SEARCH COIL FOR MINELAB GPX, GP, SD SERIES GOLD DETECTORS WITH COIL COVER PROTECTOR INCLUDED", so... will this coil work great at this detector? have anyone tried it? is it stable? this coil is compatible with "This Detech 18″ Monoloop Closed Design Search Coil for is for use with Minelab GPX, GP, SD and White's TDI/TDI Pro/TDI SL Series Metal Detectors." so... is this coil a good option? or which coil do you recomend between detech or minelab compatible with this detector? thanks

Hi, Having recovered a Whites TDI motherboard (not SL) and having a coil. I would like to reconnect it with potentiometers and switches. Does anyone have photos showing the wiring/colors of the switches and potentiometers on the plate and the values/types of the potentiometers (B100k etc.) and switches? Thanks. David

I bought Snakejim's White's Sierra Pulse Pro from the classifieds and got it this afternoon. It was a great deal and the detector is in fantastic shape and works great. I owned a beige special edition TDI SL for a while and didn't care much for it. Somehow, (maybe it's me) the SPP with the Miner Johns folded Mono 9X5 and the little Super 150 are hitting targets that my TDI SL couldn't hit even after doing a battery mod and I was using a NF Sadie on it most of the time. It's a head scratcher. This SPP is hitting small gold and lead targets that Deus 2 can't hit!!!! I mean, hitting a .1 gram nugget at 2" depth and a .25 gram nugget at 3" in bad dirt is great in my book on just default settings for a simple detector like this. Sure it is not as sensitive as many hot detectors like the SDC 2300 and GPX 6000, but it's turn on and go and this one anyway runs very quietly at the default settings and only gets an EMI warble when I turn the gain up past default. So far it is way better and more stable and easier to get running than the QED I had for awhile. It is super lightweight, EMI resistant enough to use in my backyard and is screaming on 6" deep coin sized targets that most detector miss in my test garden. This should be a really hot relic detector and a backup PI for the Axiom when it is released. Thanks Jim for offering it through DP Classifieds.

I'm curious as to the history of production and sale of the various TDI models. I know the original was called "Pulse Scan TDI" and had the large control box. Eventually that was replaced with the TDI Pro (also with large box). The SL came after the original (but after the Pro??) and its offspring were housed in a smaller, lighter housing but also used less battery power and thus didn't punch as deep. How long was each in production/distribution? And if you care to go even further, what were the prices? I think both big box units retailed ~$1600 initially and the SL more like $1300 when released, but those prices evolved. Also, did White's have MAP prices on these that differed from retail?

Hello, I'm new to this site, so bear with me if this question has been beat to death. I have a TDI Beach Hunter and I want to upgrade the battery pack, since the Whites packs are more or less extinct now. I was hoping to use the 3.7 V batteries (X3), but with how many mAh? I want to find one of these as well (see picture). Thank you very much! and happy hunting!

There seems to be much interest still on the TDI-SL mods that our friend Reginald Sniff made. I often find old emails in my junk box from people trying to get the mods. I apologize for not replying as I find them late and often busy with day chores. I will share what I still have left from my conversations with Reg many years ago. Most were over the phone as he had difficulty typing on the keyboard. I took notes and why I have the last picture with a summary of the three mods. Correspondence Reg, Thanks for the picture. I do have a few questions regarding my early model SL. 1- you had mentioned in another thread about doing something also with D20 and D21. We spoke only on changing C20, C21 and removing C56. What is the purpose of the D20,21 Mod? 2- Are C20,21 Polarized? what is the direction of flow ? ( thinking about building a board with a toggle switch to change from OEM to modified.} just in case the mod has an effect on my using my BIG coil. 3. If I did a board would the cables running from the capacitor board to the detector board need to be shielded? I just ordered the Reidman battery. Thanks Gilbert EMAIL sent by Reg in response: I mentioned mods added in 2015 to the SL to correct a problem in Australia. The mods to correct that problem included D20 and D21.. The D20 and D21 were part of that mod as was C56. You can remove D20 and short out D21 with a simple jumper to complete the Aussie mods. This will smooth out the ground balancing a little. If you use the proper caps, C20 and C21 are not polarized. Do not use polarized caps. I don't recommend a board to be added. Just tweak the Delay a little if the cap mod increases the sensitivity too much. On the latest pic I sent you, you will see an arrow pointing to C42. Adding a jumper across this cap will increase the gain and make very weak signals more reliable. Adding a jumper is easy. Simply look for two test points TP2 and TP31. They are near C42. Simply add a jumper from one test point to the other jumpers C42 and takes care of the problem. C42 and R75 are a high pass filter that isn't needed and causes problems. Eric added them when he had a drift problem and thought they would help. The drift was coming from some place else he later found out. Reg ( caps being removed are C20 &21, .47uf and will be replaced with .22uf. Use 50v Panasonic, or Rubicon Stacked Metal Film Polyester type ) from another post by Reg Picture sent by Reg My Summary of all three TDI-SL REG mods Gilbert

I am a frequent beach hunter of S. CA beaches and have found over the last couple of years that almost all hunters are using Equinox 800's. Not like the old days where you would see Fishers, Whites, a random Garrett and even a Tesoro on occasion. Which leads me to the reason for my post. My go to machine on the beach is an Equinox 800 with a 15" coil. It is rock solid, gets great depth and has rewarded me with a lot of nice3 finds. However, I also have a TDI Beach Hunter. Now before I stir up all of the PI guys who will insist that a PI will go deeper than an Equinox, I'm not going in that direction. What I am curious about is the deeper targets vs. more trash targets aspect of using one machine vs. the other. My own personal experience has been that when I have used my TDI Beach Hunter, and the competition is using Equinox 800's, I am always low man when it comes to good finds. While I may be getting better depth, the amount of junk I have to dig (rusty hairpins in particular) slows me down in terms of coverage while the Equinox guys are covering a lot more area and finding more good stuff. Have any of you had a similar experience and if so, when can you justify using the TDI Beach Hunter (or a different PI for that matter) instead of the Equinox 800? Bill (S. CA)

Is there anything that you can share on the details of getting the 16 volt battery configuration to fit in the TDI BH? I have one that I just bought, and I have heard that I can pickup a few inches of detecting depth with the 14.8v vs. 12 v stock config, and maybe even more depth with the 16v config. I would appreciate any details on whether you saw any harm to the electronics with this extra, applied battery voltage or not, the benefits of the higher voltages, and the needed case mods to make it fit? Thanks kindly. Brittany.

Hello guys, I finally signed up to this excellent forum, I had been reading it for some time and with the excuse of having bought a TDI SL I signed up to interact with you .... I get to the point, I live in Sicily, at the foot of the volcano Etna, i search more in beach, my beaches many times are very mineralized and with the presence of black sand and black stones.I bought the tdi sl for this to be able to go deeper where the vlf stop, and because I am a fan of white's quality (in my fleet I also have a v3i and I had mxt pro) I currently have two plates, the standard 12 dual field and the coiltek mono 14 "TDI series specific. I generally go hunting for coins and jewels, use the tdi with a 12.6 volt lithium battery, and do some tests by burying an 18k gold ring at 30 cm (+/- 12 ") Gain at max, delay at 10 us, threshold barely audible not annoying, gb on at 7.5, conductivity position all, is the limit for this ring. I tested it with gb off and it hears very well. By mounting the 14 "coiltek things change, with gb on, battery full, same settings as above, at 30 it detects it well. I tried to bury the ring at 41 cm (+/- 14 ") and I discovered a strange operation, if I correctly balance the tdi at about 7.5 the ring does not feel it, if I overbalance the ring at 8.5 I feel very good at 41 cm and I can even raise the plate by another 6-8 cm still feeling good. Is this behavior normal? the problem is that by overbalancing then I cannot search on the beach because the false balance signals return to me. The same thing happens by underbalancing, putting the balance to the minimum (gb at 2 or 3) the ring is heard well. If underbalance it gives it to me with a high tone and therefore low conductivity, if overbalance it gives it to me with a low tone therefore with high conductivity. also does with the standard 12 plate I therefore noticed that there is a balance range that cuts the ring, but I want to point out that it only happens when the ring is at great depths, doing the test with the ring resting only on the sand and buried a little deep, this cut is not heard, and going the gb the only thing I notice that at gb 5.5 is the limit of how the ring sounds, from gb 1 to 5.5 it sounds high-pitched, from gb 5.6 to massimo plays it in a low tone. so I wanted to understand if when the ring is at a high depth and is cut it is normal or not since overbalancing or underbalancing it can be heard, while with the correct gb it is not! the metal is as new it is from 2020. I only have the doubt that at high depth the ring is exchanged with the same level of ground balance and therefore cuts it to me even if it actually feels it. The Problem that I can't walk on the beach over-balanced, it's impossible, so when I balance correctly now I always have the doubt that I will lose rings in depth ...... I have read Steve's guides, I hope he can answer too .... . soon I will make another 16.8 volt lithium pack, I wonder if the problem will recur ... I apologize for the long topic but I had to explain everything correctly goodbye and thank you from the land of oranges and lava Salvo

Hi, Is there a modification to have on the TDI Beach Hunter the same "Target Conductivity" switch as on the TDI Pro / TDI SL ? Ie all sounds, or just "High Conductor" or just "Low Conductor"? I had a TDI SL and I might buy a used TDI Beach. Thanks.

I want to make a mono search coil for tdi sl. Can you help with the search coil values?

I just watched this Whites Video with Josh Bohmker. He found a way to take a couple of D-rings similar to those on the old Goldmasters and chest mounted the SL. Very cool!

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.

Curious if Sun Ray or another 3rd party vendor made an inline probe for the TDI? Thanks in advance! Gabe

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

Would like some help please on a specific coil for my TDI Pro,i have the option of buying this brand new Coiltek 6'' Mono coil which was of course specifically designed for the GPX range of detector,the GPX Mono coils do work very well on my TDI Pro as i own and use most of them on the TDI. Has anyone specifically used this small 6'' Mono coil i am looking at using it most of the time because i am using smaller coils more and more due to the problems that i am hving with a broken wrist that i had from a bike accident decades ago,does anyone have any thoughts on this combination please.

Well I decided the TDIBH was too much of a handful in the water so I decided to move it on to a new owner. Hopefully I’ll not regret the decision but I got what I paid for it so can’t complain too much. One of Whites best for dry and wet sand hunting but never got much market penetration....I guess most want VLFs these days ? Time to change my profile.......just five machines now 😳

As I mentioned some days ago, I was afraid to have a non waterproof control box after minor works on the coil's cable and the PCB inside. The final result of this morning Is been: lot of unstable treshold drift since a few minutes inside the water(no way to calm down the treshold even with GB off). Some minor short cause I can see the voltmeter crashed and fuc...d up... After almost two hours of terrible noise and a few real signals, nothing to Say but a finally stable treshold without signals at all when targets were under or over the coil... This means to me:the coil isn't working anymore... Maybe the dumping resistor? Maybe the lower resistance due to the cable shortening? Nope....The gasket leakage and maybe the connector too. I don't even have the time to dismantle again today..🤬🤬🤬🤬 Pissed as usual Skull

I am still need to metal detecting and learning an original tdi. So lately I have been experimenting with the different controls and how they affect the machine. I read some instructions that mentioned running the gain at the point that the threshold remained steady and did not waiver. This typically leaves me with a gain of 3 or 4. Does this sound right or am I missing something?

I've been experiencing lower yields due to sites being detected, by me for sure and there are also signs by others previously. SchoolofHardNox's success on a beach using the Minelab GPX 5000 reminded me to re-read Steve's treatise on using the (in his case original big box Pulsescan) TDI for coin detecting. I just a few days ago stumbled upon a promising site where extra depth could be key. It's a schoolyard going back at least to 1955. Unfortunately as is the case in many of my public sites, it has a history of backfilling. From aerial photos I see than in the 50's it was grass/sod covered but in the early 60's they put down gravel. The person who told me about the site (a person who walked up to talk when he saw me hunting a nearby park) said he was a student there 45-50 years ago and at that time it was (again) grass/sod. I did a one hour survey hunt with the Minelab Equinox (11" coil) and encountered a couple inch thick gravel layer about 5" down. I did find one Wheatie below the gravel, but 7" is getting deep for my detector + soil mineralization combination so if coins remain from the 50's (pre- gravel layering) then I expect I will do better with extra depth (and that may even be required). One thing I've found in my detecting of these older sites -- there are always nails present. So even if my TDI/SPP can deliver in the coin category it's going to be signalling on a lot of nails. One of the tricks Steve used was to set the conductivity switch to high conductors (low tones) but the TDI/SPP doesn't have that feature -- I will be hearing both high and low tones. This is a dual disadvantage -- extra tones to have to mentally tune out but also extra threshold noise since both parts of the signal spectrum will be contributing to that as compared to only half when the conductivity-low switch selection is made (on all TDI's except the SPP version). Here are some specific concerns: 1) Am I fooling myself thinking I can get extra depth with the TDI/SPP, particularly when it comes at the expense of a noisier threshold? 2) Which coil(s) should I be using (choices I'm considering are 6"x8" Nugget Finder Sadie mono, 7"x14" NF mono, and 12" round White's 'Aussie' mono)? 3) Should I flag the promising targets but double check with the Eqx 800 (and if so, should I use the 11" or 12"x15" coil on the 800)? (Note, even if I choose this route I will likely at first dig, regardless of what the 800 says, just to get an idea of what is giving the signal and how deep the targets are.) Any other advice (from anyone) is appreciated.

I have an easy and maybe stupid question to present now... Observing my TDI Bh, with both of the coils I own (the original 12" and the aftermarket Detech 8"), I can clearly see way too long wire around the shaft and I'm forced to make several loops up to the control box near the handle. Supposing to measure the right lenght for the maximum extended shaft, and to cut away the hipmount mile long cable.....Am I doing a disaster or not? I actually can't remember the technical cable's specs in the amazing pdf Steve posted time ago, but if I'm correct it talked about to reduce some current resistance with a slight performance improvement too...Have I seen a mirage or what?... I'm not kidding 😜... It's just me, looking for something to play with, suffering for a missed AQ.

This maybe a newbie question but, what is the difference in the 12" Dual Field Coils pictured here other than the black and white labels? Is one 1st gen. or 2nd gen. or something else? Thanks, TC-AZ

I am interested to learn more about the 7.5-inch mono versus the 7.5-inch Aussie coils that are available for the TDI series. Is there an advantage of one coil design over the other when hunting for nuggets? I have the standard 12-inch dual field and also a Super Pulse 150 coil and am curious whether I should add either or both of these coils to my collection? Or should I purchase one of the new Nugget Finder 8x6 Sadie mono coils? Any thoughts or advice would be greatly appreciated.

I opened up my TDIBH the other day for some fiddling around and checking out a few things. I powered up the detector with all of the guts and board opened up and had it hooked up to the 14.8v (4 x 18650 cells) battery pack. I had it going for just a few minutes when I gripped the circuit board as part of my “fiddling” around......well I dropped the board and swore a bit in response the burn I was expecting on my fingers. Well it turns out that on the opposite side of the board behind where the big capacitors sit is some sort of heat sink and I can tell you the heat from this spot was something else. The detector has and runs just perfect but the hotspot really surprised me. I decided to hook up the 12v battery pack and let it run for a decent amount of time and it never got past a mild warm on the back of the board. That extra couple of volts is generating some serious extra heat.....bit like on the heat sink area of the CPU chip in your computer. I honestly don’t know if the detector can handle this extra heat long term but I’m not taking any chances. I’ve moved back to the 3 x 18650 battery pack which I knocked up when I first got the detector. There is a slight loss in depth but surprisingly not too much. I feel the performance of the 11.1v Lithium setup is maybe 1 to 2 inches behind the 14.8v “hot pack”. You can see in the photos the big caps on the detector and where the heat comes from. The other photo is my 11.1v pack which packs some punch and lasts much longer then the stock NiMH pack.