Whites TDI Pro Oz mods

[alwayslooking]

I picked up a 2nd hand TDI Pro Oz last year and like it very much. It works well with the 6X8 Nugget Finder and the 7 1/2 X 11 MJ but I can't seem to be able to get the gain above 5 without it getting too warbley. I have the pulse delay at 10 and the GEB in ALL when using it on gold. I was just wondering if this is normal or am I doing something wrong ? Is there a mod of some kind to increase the sensitivity or is it not worth the effort or $$ ? I have found gold with it but wonder how much small stuff I am missing. Thanks, any info would be appreciated.

 

[Ridge Runner]

Well you need to adjust the frequency at tiny bits at a time, For some reason PI machines suffer in OZ from bad EMI, In the UK I can Max the TDI Pro flat out in the City, even in side the house.

 

[grubstake]

I picked up a 2nd hand TDI Pro Oz last year and like it very much. It works well with the 6X8 Nugget Finder and the 7 1/2 X 11 MJ but I can't seem to be able to get the gain above 5 without it getting too warbley. I have the pulse delay at 10 and the GEB in ALL when using it on gold. I was just wondering if this is normal or am I doing something wrong ? Is there a mod of some kind to increase the sensitivity or is it not worth the effort or $$ ? I have found gold with it but wonder how much small stuff I am missing. Thanks, any info would be appreciated.

There are actually two models of the Pro, but I don't know whether this also applies to the "Oz" branded detectors. The original model used thru-board mounted components and the circuitry included a number of screwdriver-adjustable pots on the circuit board. You tamper with the factory calibration settings at your peril, but some tweaking is possible. The revised model uses surface mount components and replaced the adjustable componentry with firmware, so there's nothing that's user tweakable. There's a minor difference in the casing graphics that allows the models to be distinguished without disassembly, but I can't presently recall it.

I'm trying to remember where I saw all this - possibly findmall.com and mostly from Reg Sniff's detailed postings. He used to Post here on PA too - these are the posts where he contributed something:
https://www.prospectingaustralia.com/forum/search.php?search_id=2133426114

There's a ton of info in those - have fun searching!

 

[karelian65]

Warbles on the Tdi Pro are normal, a characteristic of this machine. There are mods available but they might or might not be the right answer.

You can push threshold past the warbles until it smooths out, then turn down the volume, but gain will still be around 5 for bad ground and the machine will be noisy. I find the noise distracts me so I use a technique I've ripped from Wal&Liz, run silent with extra gain...

I put a grommet under the threshold dial so it only moves with effort. Thus equipped I run the Tdi Pro by starting with threshold loud past the warbles whilst I ground balance, once properly balanced I move threshold to just silent, then up the gain higher. This method allows higher gain without noise, with the grommet under the threshold knob I know it won't move and after a lot of second guessing I have confidence in this method. It works for me, it is an option.

Should point out my Tdi Pro has mod for smoothing out the warbles. The mod allows more ground noise and some hot rocks will register, not a big issue for me since I focus mostly on the beach, could be a deal breaker for prospecting. Mod only takes effect when ground balance in on..
If I had to do it again I would focus more on technique, gaining experience and confidence in my abilities with the machine, maybe not worry about the mods.. My opinion only.

The Nugget Finder Sadie you are using is probably one of the best small gold coils, my experience. Spoke with Gold Search Australia, the local importers recently and they told me that sometimes in bad ground using LESS gain can produce better results, true for VLF machines but I'm still on the fence for PI machines. The argument was that running a smooth and stable machine enables you to pick out targets more easily. More gain is not always the answer. Dean runs his gain around 3 or 4, still finds the gold.. Next time I'll give it a go myself. Experiment, test things out, it's all part of the experience.

Good luck with the Tdi Pro Oz, I've got a lot of respect for this machine. It's great on the beach, very capable on the goldfields and good fun to boot..

All the best,
Karelian

 

[BushChook]

Dean has 2 tdi pro ozs, one modded and one unmodified... Unfortunatly dean does not do the modifications any more. There was stage 1 and 2 upgrade. I was just interested in the stage 1 upgrade which smoothes out the threshold.
Anyone know of someone who still does these upgrades to the tdi pro oz that i can have a chat to?
Any more info about the modification your tdi has karelian?
Thanks

 

[Roscoe]

alwayslooking, There is two ways to run this machine for gold.

One method is to raise the gain just before the ground balance window gets to narrow and stop. Depending on soil mineralisation the gain with this method can range from 3-4 in high mineral to 8-10 in benign soils and anywhere in between. You can run this method in ALL or Hi/Lo conductivity.

Second method is run the machine in 10 usec, 8-10 gain all the time and raise the ground balance slightly higher in Low con. mode and slightly lower in Hi con. mode and shift the conductivity switch to your prefered target conductivity, eg Low mode for small nuggets and high mode for large nuggets. But you can only be in one mode at any time.

My preference is for the second method 1- It removes 50% of the unwanted external and ground noise from the detector straight away. 2- It gets better depth on targets in general, but it can knock out small targets in some situations (can explain this later if required). 3- It eliminates large iron and other high conductors including unfortunately large gold nuggets. But the big plus is the detector purrs over the ground and you won't be digging up ground noises, you can cover ground fast and the machine runs very quiet.

I like to think of the second method like a sluice box, you can make it more efficient at catching finer gold, but this will slow the amount of material through the box. At the end of the day, it's not always what you are missing but what you have found.

Don't worry about the mods until you give this ago first.

 

[ronniecruisin]

Hi.all. Have read a bit re modding a tdi to increase depth capability. Does anyone know if this can be done DIY ie photos before and after and details of the parts and where they go so someone like me could do it with little electronic knowledge but with good soldering skills and working with small parts.... Regards.... Ronnie. :argh:

 

[mbasko]

The only depth mod for the TDI I've seen is to increase the voltage to a 16.8v pack.

Other mods were to smooth the threshold & for small gold sensitivity/faster sweep speed. My belief both of these mods are now factory done in new TDI's but I can't confirm that.
The sensitivity/sweep speed mod requires removing & replacing 2 caps which probably should be done by someone experienced with the TDI or with electronics?
"The caps being removed are C20 & 21, .47uf and will be replaced with .22uf. Use 50v Panasonic, or Rubicon Stacked Metal Film Polyester type." Credit to Reg Sniff

Another mod was to decrease the pulse delay to 8us by adjusting the pot.

If you Google "Reg Sniff TDI mods" you can find more details & Reg's contact details. He may respond with more detailed info or point you to someone in Australia that can help. There is at least one Aussie who was assisting with TDI mods awhile ago.

 

[ronniecruisin]

Hi mbasco. One of the forums is where I saw reference to this and it was Reg. Apparently its possible but the trade off is the tdi's ability to discriminate. I just wondered if anyone has actually done it and if so ...how? I'm thinking the mod would possibly bring performance very close to a mlab.

 

[mbasko]

You could try contacting Reg directly:
https://www.prospectingaustralia.com/forum/profile.php?id=3659
[email protected]

 

[ronniecruisin]

Good idea. I'll try that. Thank you

 

[grubstake]

Hi.all. Have read a bit re modding a tdi to increase depth capability. Does anyone know if this can be done DIY ie photos before and after and details of the parts and where they go so someone like me could do it with little electronic knowledge but with good soldering skills and working with small parts.... Regards.... Ronnie. :argh:

Maybe/maybe not - apparently it depends on whether yours is an early or later model of the TDI:
https://www.prospectingaustralia.com/forum/viewtopic.php?pid=315005#p315005

My understanding is also that at least the early TDI SLs used a TDI Pro circuit board with reduced functionality, so you may find some guidance about what you are seeking by contacting gflores71 at the email in his May 2019 post on the Detector Prospector forum:
https://www.detectorprospector.com/forums/topic/8862-tdi-modifications/?tab=comments#comment-95742