CaliGold

On 1/7/2024 at 6:59 AM, Tom B said:

What are you asking for it 

999$ obo shipped UPS from Santa Ynez. gotten NO offers. zzzzz

pat

13 hours ago, PI-Man said:

Very Nice setup.  Someone’s gotta want that.  One of the best machines out there.  They go very deep.  I have 3 with mods and a bunch of MJ coils before he got shutdown from fire.  None of my machines owe me a thing they have paid for themselves a couple of times over.  Good luck with sale.  

I love in your bio where it says "whites tdi sl, they might be tweaked a little" lol

On 1/7/2024 at 6:59 AM, Tom B said:

What are you asking for it 

950 +/- shipped from Santa Barbara County. OBO obviously... 750 without extra coils.  Haven't gotten an offer yet. WE SHALL SEE.  I have a sdc2300 Mine Lab in route to me too. This was a great detector, I just need something more sophisticated with LESS settings for small gold and waterproof. I'm a river rat so this thing has to be babied near rivers. Note, it has never been swimming... The waterproof and basically one knob Minelab is up my alley...  Trying to sell/ship before I leave town Sat for Colorado. Reasonable offers will be entertained. I take paypal and will ship immediately. There's a ups store up the road here in Santa Ynez. 

Pat

I have a 2015/2016 whites TDI SL tan edition for sale. It has been used seldom to in-frequently and VERY little in the past 2 years. Almost less than 5 times.  I did some mods to it and it works great. (thanks to the community here for the coaching) You can see mods in my posts. I have a 14" coiltek tdi series coil, a Nugget Finder Sadie Coil sika flexed for waterproofing (tested 3 times then hunted  once in East Fork river works fantastic) bought a few months ago, the stock Miner John 8x12" coil, and a modded panasonic 16v battery pack and the regular AA batter pack. I used the stock nimh rechargeable battery pack to make the current Panasonic 16v pack. I have the stock charger base (lost the cord/adapter). The detector has lots of gain increasing mods and includes a "boost switch" to control a bypass on a removed resistor. I've tested it a bunch since all mods were completed and it works awesome. I will note that the 14" coiltek tdi series coil should be used with the lower voltage battery AA stock pack. I suppose you could make a 3cell- 18650 Panasonic  pack for that coil if you must have it. I'm getting a minelab from up north since I was trying to turn this puppy into a minelab. Not Happening...  I'll add some pics when I can. 

Let's hear some offers.....

*Full Package -$950 OBO shipped.

*Without coiltek and NF sadie coil and includes only the Miner John 8x12" coil (great coil) -$700 plus shipping

Either package includes: 18650 battery charger for the panasonic batteries and an orange Nokta 2019 Pinpointer (runs on 9v).

Thanks

Patrick

email for more pics info to talk etc. patrick@patrickwprice.com 

@Jim in Idaho @PI-Man @Melano87 Alright gentlemen...

Went up to San Gabriel River East Fork this week. Took the TDI SL for testing and to see the condition of the riverbed after all the rain this past year. Haven't been there in a while as its usually packed with tourists in the summer and the water level has been high since we got lot snow/rain in the winter/spring too. 

The TDI was great. Found bird shot in bedrock crevices like nobodies business... The side of coil sensitivity is very good. Chiseled  chunk off where BB was down an inch or so in behind the slab (sorry no photos), so this was a good "gold scenario" test for areas where the bedrock type and river flood stage are more conducive for nugget hunting. Anyone who has been to this area knows metal detecting is usually fruitless near the river downstream from the Bridge To Nowhere (5 mile hike from parking lot) or unless you're up on a bench. There was heavy helicopter activity that day so the bench I had planned on scouring was, lets say, "occupied" with powerline maintenance and Helis... Is what it is. There is simply too much trash in the stretch of river adjacent my originally planned bench to detect unless you are game to dig lets say 5,000 targets in a day... (nope)... This is a known sluicing dominated river and crevicing/detecting WAY upstream somewhat...  At any rate, after finding tons of trash and several birdshots, and a 1975 nickel at the old Eldoradoville town site, I took to the stream bed to sample some virgin 2023 flood gravel. I classified some nice average fist size Jenga gravel (literally off the top of the ground) to  about 3-4 gallons of 1/4" to 1/2" material and panned it out slowly. Got some fine gold, amalgum, to at least say I didn't get skunked... I also got to test out my satellite messenger (Zoleo) which worked great even in the canyon, or when driving and device on dashboard. I HIGHLY recommend anyone prospecting out of cell range to get one of the many options for these types of devices. After I'd say 2-3 hours of on/off detecting before starting my pan sampling, the detector still sits at 70% battery. I'm happy with the mods and excited to hunt down some nuggets upstream or in a better river up North, and more importantly glad I got out for some river time, fresh air, and a good 8 hours of moutain ops helicopter viewing. Only my second trip out all year... My profile pic and banner was last trip to Tuolomne county couple months ago for some panning. Much larger gold there to be had. Pickers a plenty in the motherlode...  (You can see in red circle the patch of gravel I sampled. I'll definitely sluice this spot if the gravel is still there next time up). A lot of guys go upstream, so with the rain this year, I think downstream is a little nicer than usual. )

-pat

@Jim in Idaho @Melano87 @PI-Man

I took the plunge and removed R86 resistor and made the sweep speed mod yesterday with some gucci $ caps I found on digikey to spec recommended. Machine seems ok in air tests. 

List of Mods:

-Q4 mosfet "beefed up" and heat sink added.

-R9 & R14 resistors wattage increased  2 watt on R9 and 3 watt on R14. (3 watt much thicker but fits fine 2512 size footprint)

-C42 Jumper and on/off switch installed and mounted on control panel exterior. 

-Sweep speed Mod (C20 and C21 capacitors swapped). Digikey part #s SMR5224J50J02L16.5CBULK
399-13054-ND
 

-R86 resistor removed (near gain plug) (easiest "MOD" to complete lol)

-16.64V battery pack (my charger wont go past 4.16 on each 18650 battery)

-I have waterproofed my 8x6 Sadie coil from Nugget Finder with Sikaflex 221. (hard to find other than amazon or an RV repair shop...

I find the machine runs great with gain up around 50%-80% and with Gain Boost switched on from c42 around 50%.

God have mercy and bless this machine to find much Gold. 

Thank you, again, gentlemen. I hope I don't let you down. 

Patrick

On 9/7/2023 at 9:12 AM, Geotech said:

R86 slightly limits the max gain. Removing it increases the max gain by 10%.

Thanks Karl!

@Jim in Idaho what do yo think of this idea Jim? Karl is the guru obviously but has anyone got any anecdotal info on this? @Melano87 know anyone who did that-  removed R86?

Very tempted to remove R86 and still on fence with swing speed mod. I waived a .15gram (about just shy of 2 grains) test gold flake in front of sadie coil fast today and it got good decent signal at 2 inches so maybe unnecessary? 

Does gain increase depth or is that only possible by current from battery etc? (man I want to use that 20v battery again) Terrified though... Maybe if I swap out R9 and R14 current 2 watt resistors for 3 watt (I just got some) The Q4 installed with heat sink is already a higher rated voltage model with some different specs here and there that as a lamen  I read to be an "upgrade". 

Looking forward to the days when my posts on here are the "look at all this Gold I found with my modded out SL" sort...

Many thanks, gentlemen. 

@Geotech anyone here know about removing R86 resistor down by the gain control area? Saw online... Is that flying too close to the sun? Thanks! p.s. thanks again on the schematic etc. Switch on c42 went well... works good.

-Pat

On 9/5/2023 at 12:56 AM, Melano87 said:

Great job !

 

For losing depth :

 

Thanks for the thread link. Interesting. So upon testing the new c42 jumper switch I installed, I found the increase on signals to be pretty intense. It makes the machine run a little hot but maybe that was just the sun and the 16v battery I was using. The gravel in the river bed I test in is pretty intensely mineralized. I guess thats why the wine around here is so good. 😉    Noise goes up a bit with switch on but I slowly learned how to harness the extra gain. It's a nice option to have and I imagine it will be especially nice on bedrock with more continuous surface ground signal coming in to base GB off of. I'm glad I did it. It allowed me to run my AA battery pack that I brought which sat at around 11.5 volts and then kick on the Gain Switch and punch deeper on tests. I didnt do measurements on all targets but lets just say IT WORKS and I hope anyone using this mod is well versed in tuning GB, Frequency, and Pulse Delay with test targets at the actual site of detection or prospecting. Very powerful in the right hands. ... I also tested my water proofed sadie coil (sika flex 221) and all was well there... Good signal above waterline to 6" deep to that 1.1gram nugget in the ziploc bag and no issues underwater. So Far So GOOD.

Here is switch installed. Tight space there.  A little close to the caps lower down on board inside but cleared ok with no contact.  Debating on doing the swing speed mod when caps arrive this week. @Melano87 mentioned losing depth on this mod? 

 @Geotech or @Jim in Idaho  Did you guys notice any depth changes/losses on sweep speed mod? Thanks!

On 9/3/2023 at 5:52 PM, Jim in Idaho said:

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

Karl is the man no doubt and you guys went to great length to share your mods so I thank you again. I did the c42 jumper/on/off switch mod tonight. Taxed my skills a bit but it works. With the switch on and the gain boosted the machines emi went up a bit and I had to be careful what direction I held it in in my garage as the sadie coil was picking up anything in the structure. I put it in low conductor and GB off and it  tamed down a bit. I WAS able to run GB on later in testing but I put it back in low conductive mode to avoid the coil sensing everything "big" in the garage.   I was able to get it to stabilize for some hand held air testing of my sample gold nugget targets. The side of coil sensitivity went up on all sizes as did depth. At least 25-30% it seemed.  Great mod so far! I may switch the R9 and R14 2512 sized resistors out for 3 watt (have 2 watt installed now, originals were 1 watt) as the battery was a little "warm" when I removed it after about 10 minutes of testing the gain switch. I'll do backyard quartz pile testing tomorrow maybe even hit river and bury some gold. 

1 minute ago, Melano87 said:

Sorry for the response time.

No, I had exchanged with several people, and I had not installed a 1k resistor in series.

And I use it like that.

Is this a mistake?

No worries. I'm sure we all have lives outside looking for treasure...

Do you notice and depth increasing on signals with this mod? Sensitivity to smaller targets? Please share your thoughts  on the performance you've notice if possible.

Geotech recommends a 1k resistor in series with the switch to the test points. Learning as I go..

many thanks

Patrick

3 hours ago, Geotech said:

Here is a diagram for clarity. I've labeled components both for the SL and the [TDI/TDIpro]. Note that only the SL has test points.

I have never tried this mod so I don't know what the results will be. The purpose of C42/R75/U7d is to eliminate DC offsets and reduce bounce-back noise but maybe it's overkill. If all you want to do is short C42 then I recommend lifting pin 10 of U7 [or removing Q16] or cutting the trace.

 

Thanks Karl! and @Jim in Idaho The metal detector Gods have spoken...

pat

On 8/31/2023 at 7:43 AM, Melano87 said:

The jumper is made with the Test Points 2 and 31.

When I made this modification, I soldered a wire on the TP31, a wire on the TP2, I installed a switch (2 positions) next to the speaker (only place really available), I twisted the two wires up to the switch.

Why a switch? Because as the gain increases you have to be able to “control” it and there are places where it is difficult. So when I need it and possible I put it in the ON position.

Don't touch R9 - R75 - C42

On TDI SLs manufactured after 2015, D20, D21 and C56 are absent (modification taken into account by Whites). On those before 2015 they are present.

 

I also installed a potentiometer for adjusting the audio volume (like on the Beach Hunter)

You did not use a resistor? This mod is stumping me. I've been told all sorts of tech stuff I don't understand. "across" "covers" "opamp abuse". Thanks

On 8/31/2023 at 3:38 PM, CaliGold said:

Do you think the switch is necc with smaller coild than yours? you have some behemoths there... My biggest coil is a 14" coiltek tdi series round mono....

So you didnt use a resistor? Thanks

3 hours ago, Jim in Idaho said:

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

Thanks Jim

Completely lost as to what that means tangibly. I know you guys are trying to educate me, but I think I need direct orders. soooo, Solder a 1k resistor in-line somewhere along one of the two wires going to the toggle switch between the two test points? I'm basically gonna solder one wire to Test Point 2 and another wire to Test Point 31 and  neatly route and connect those two wires to the two different tabs on the bottom of this switch in photo below. I'm clueless as to where to put a resistor in this scheme. I ordered these 0805 resistors and sounds like they are the wrong kind. I'll have more time tomorrow to take crack at it. I just put that resistor on top of the cap in photo to show scale. Why God Why.

Thanks

Pat

On 8/24/2023 at 11:42 AM, Geotech said:

As it turns out, the factory TDI coils are a major performance limitation. I've adapted an Impulse AQ coil to run on the TDI and can then reduce the minimum delay to 6us. It's still not gonna run like a Minelab, but it is a little more respectable.

 

Was this the TDI SL or TDI Pro? Obviously I'd love to lower the pulse delay to 8us on my SL. Is that even possible? 

41 minutes ago, Jim in Idaho said:

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

Ok, so solder the resistor right on top of the cap at c42? sounds fun... Then wire from the test points to the switch I assume. Unless I'm imagining this wrong...

Yes, looking forward to some testing too!

Thanks!

Pat

On 8/31/2023 at 4:31 PM, Geotech said:

Output of the opamp.

The C42 mod should have little to do with coil size. The purpose of C42 is to remove DC offsets before the final gain amp, which has to do with the circuitry and not the size of the coil. As Melano says, as you crank up the gain of the final amp (with the GAIN control) the DC offset gets gained up and can cause noise issues. I've never done this mod so I can't otherwise comment on its effectiveness.

The absolute values of C20 and C21 don't matter much, even 10% caps are fine. Just make sure they match each other within 1%.

I will have a 10mm mini toggle on/off switch with rubber boot (could only find 125v to ship fast) and a 1kΩ 0805 size resistor tomorrow to go for this C42  gain mod. Do I need to remove the current installed C42 component and replace with the 1kΩ resistor to accompany the test points wired switch or does the on/off toggle switch make the resistor unnecessary?  The .22uf Caps are inbound, but shipping slower. I think that will cover all the possible mods on TDI SL 2018. Someone mentioned in a forum that the c20 c21 sweep mod caps were changed at factory after a certain date but mine are stock .47uf indeed...  

SIDE NOTE: I'm getting getting really good side of coil response with sadie coil 8x6  on these gold nugget samples especially see pic below. I buried the 1.1 gram nugget under a fire brick and 5" of Randsburg, California quartz samples and it was a great signal straight over the pile with room to spare. I also Sikaflex 221'd the coil cable inlet on the coil. No bedrock stands a chance now... 

Many Thanks! 

7 hours ago, Melano87 said:

The jumper is made with the Test Points 2 and 31.

When I made this modification, I soldered a wire on the TP31, a wire on the TP2, I installed a switch (2 positions) next to the speaker (only place really available), I twisted the two wires up to the switch.

Why a switch? Because as the gain increases you have to be able to “control” it and there are places where it is difficult. So when I need it and possible I put it in the ON position.

Don't touch R9 - R75 - C42

On TDI SLs manufactured after 2015, D20, D21 and C56 are absent (modification taken into account by Whites). On those before 2015 they are present.

 

I also installed a potentiometer for adjusting the audio volume (like on the Beach Hunter)

Do you think the switch is necc with smaller coild than yours? you have some behemoths there... My biggest coil is a 14" coiltek tdi series round mono....

50 minutes ago, Jim in Idaho said:

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

Hi Jim, here is closeup of c42 (in blue) and those Test Points 2 and 31 ( in red)...

so your opinion is valuable too, do you think with coil below 14" the on/off switch on this c42 gain mod is absolutely neccesary? Thanks!

Pat

56 minutes ago, Geotech said:

The caps can be just about any film-type: polypropylene, polystyrene, PPS, etc. What you want is a cap with low microphonics. Then you want to match the 2 caps to 1% or better. So if you get 2% caps, order 4 or 5 of them and then hand match two of them with a cap meter.

On C42, I would not put a dead short there, rather put a 1k resistor across it. The reason is, there is a switch (U7d) that grounds that node and by shorting C42 the switch now grounds the opamp output (U12a). That's called "opamp abuse" and no one wants to be accused of that.

 

Thanks Karl!  If you have time can you comment on weather a on/off switch for this c42 resistor mod would be helpful or even necessary if one like myself is running mostly a 8x6 sadie with largest coil being 14" Coiltek TDI Series mono. (and the Miner John 8x12 on occasion). I'd rather avoid making the on/off. I would even forego using that 14" coil at all on this machine if the gain mod would make the switch absolutely necessary. 

*Also thanks for info on the c21 etc caps, sweep mod. They're hard to source online below 5% or 10% tolerance. Can I get away with say 3% or 5% tolerance on the cap models? I realize the "pair" ultimately used will have to be 1%...

ALSO... Man! you guys are quick with the helpful info! I owe you guys lots of gold found pics and imagery. I promise this fall/early winter will be epic...  I definitely owes you guys one on the DP forum.

2 hours ago, Jim in Idaho said:

Pat, what you want are stacked metal film caps. I think the ones I used were .22mfd. Gary Brown down in Florida ( an SL user and electronics tech) sent them to me. He sent me a couple of different pairs. The ones I have left are Rubycon IH224J. The capacitance varies with frequency, but averages about .222mfd. Get the closest matched pairs you can. I don't recall exactly what these are...either 1 or 2%

Jim

Yes I know what yo buy just no one has them and digikey and mouset say they’re obselete and panasonic doesn’t make them anymore. I posted a pic of what digikey said was “similar “ it had 63v which is fine but they’re 2% tolerance. I’ll probably order them and instal this next week. Thanks to all for clarifying the gain mod with switch. How much gain are we talking? Is it bad to not have the switch installed? Would the machine go haywire using the normal gain pot? 

@gflores71 on making the "jumper" on c42... How and  what am I soldering together here? The two test points mentioned or? The nomenclature from the email got me a little confused...  I see how the three pad diode smd was removed at d21 a  "jumper" was completed but the c42 is a two pad resistor smd. Are we wiring the two c43 pads together after removal of resistor or one of the test points to one of the pads or both? I'm lost...  Also,Does R75 resistor get removed/jumpered too? Thanks and sorry to pry but I'd like to complete this mod asap and get some testing / results posted for any other folks out there that were left looking for more sensitivity from the TDI SL.

@Jim in Idaho please freel free to share your knowledge on how this mod would be completed too (C42 and R75)

Thanks so much again to everyone. 

Pat

On 1/8/2022 at 10:01 PM, gflores71 said:

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

 

 

Hi Gilbert

I have been modding my TDI SL lately. (just the battery and coil resistors as the diodes and jumper were done at factory.  I want to complete the sweep speed cap replacement (c20, c21) as the .47uf are still installed but cant find the panasonic caps of that spec ANYWHERE and digikey parts says theyre obselete now and suggests below replacement. The difference is? There is also a 2% tolerance instead of 1% difference that someone mentioned earlier thread I think it was @Jim in Idaho. Does that matter? Any lead on the .22uf 50v 1% throughole caps would be much appreciated. 

Patrick