TDI mods

[Beach Bandit]

The 1st or early TDI has the most controls,then the Pro has the same size control box but has a couple less contro knobs..The SL is near 3lbs in weight compared to about 5lbs with the other two..and the control box is smaller.I haven't heard of any difference in performance between the 3 machines just the SL doesn't have all the "bell and whistles" as the other two...

[Orbit]

My mod ....https://www.youtube.com/watch?v=w6p9kOlYITs

[Carl-NC]

The 1st or early TDI has the most controls,then the Pro has the same size control box but has a couple less contro knobs..The SL is near 3lbs in weight compared to about 5lbs with the other two..and the control box is smaller.I haven't heard of any difference in performance between the 3 machines just the SL doesn't have all the "bell and whistles" as the other two...

Eh, not exactly... the Pro has 2 add'l controls: fine GB and volume. SL has slightly less raw depth but also runs quieter (less chatter), same bells & whistles (controls) as the std TDI.

There is also a "Sierra Super Pulse" (SSP) variant of the TDI, which is an SL with a fixed delay and no freq offset as I recall, and it might be all-cond only. There may be another TDI model made for the African market, I don't recall.

Addendum: There is also a TDI-Oz variant of the TDI-Pro, which is identical to the Pro but has a true mono coil instead of a DF coil.

[Beach Bandit]

I think the TDI and the TDI Pro each have 8 dials and switches.The Pro has volume control where the TDI original doesn't.With the 2 mods done to the 1st TDI the machine is very stable and quiet,also can run the gain high.Ive owned the SL but sold it and kept the TDI 1st model..

[greylourie]

Some TDI Control Boxes and SL (SPP) pcb screen capture.

I have some images I leached from various places on the internet.

Very early TDI.

TDI Pro.

Early TDI (also listed as TDI 300 on some vendor websites).

TDI SL.

Whites GMT SuperPulse ("Al Monshar") / Whites SPP.

I think Geo posted an image of his TDI pcb, somewhere here on Geotech.
And on https://www.prospectingaustralia.com.au/forum/ , you can find an image of the SL/SPP pcb. They have differences. It appears the SL/SPP has a few features that for some reason Whites decided not to implement. Namely "GRAB" and "GB AUTO/LOCK".

Amazing machines.

[Carl-NC]

It appears the SL/SPP has a few features that for some reason Whites decided not to implement. Namely "GRAB" and "GB AUTO/LOCK".

When I designed the SL I threw in some hooks for development work I was doing on ground tracking. That work turned into an entirely different machine and the methods I developed didn't work on TDI. So there are no unimplemented features on TDI, just unused hooks.

[greylourie]

Nice to get that little bit of history. Other aspects show change, as well. For example on Geo's image of a TDI pcb there are a lot of trimpots and poly caps. The sl/spp board is much cleaner looking, and has some type of card edge connector etched and milled. Very nice work.

[Altra]

I have some images I leached from various places on the internet.

Very early TDI.[ATTACH]33470[/ATTACH]

I actually own this TDI in the photo. Inside the battery door its marked "TDI-1". It has pcb's marked
PPD6 for Pulse Power Developments 6 and a audio board made by White's. This would have been the Goldscan 6
if Whites hadn't license the design. It is for sale if anyone is interested.

[Old cart]

Does anyone know the serial numbers for the early thru hole versions of the TDI?

[greylourie]

Perhaps ask Altra. He has one for sale.

[Altra]

You would have to ask Carl about serial numbers he was fully involved. Mine does not have an official serial number
it is marked "TDI-1" and was probably one of the prototypes sent out to testers.

[Beach Bandit]

Altria.....Was your TDI on e Bay for sale a few months ago.?....What were you asking for it.?...Regards.

[Carl-NC]

Tan-colored TDI's were protos. The 1st 200 thru-hole units had a different silkscreen marking for the conductivity switch.

[Altra]

Altria.....Was your TDI on e Bay for sale a few months ago.?....What were you asking for it.?...Regards.

Yes this unit was on Ebay. The photo from the listing was posted above by greylourie "early version". The seller sent it with a White's vlf coil, probably why he didn't like the performance. In the photo notice the black coil cable, the TDI coils all seem to use the gray cable. When I hooked
a minelab gpx coil it worked great. I was going to mod the unit, but thought maybe better to keep it original. I am selling for $560 plus shipping. This is for the box, battery and charger. No other accessories. PM if interested.

[Beach Bandit]

I was bidding on it on e Bay,,he had it listed I think 3-4 times,I think he changed opening bid price then resisted it..There were no shafts,I think just the box and maybe a coil..I figured this was the one,,how many proto units would be around..I ended up buying an SL and sold it then bought a TDI and sent it to a friend Reg has doing the mods..I wondered if yours was found maybe in a storage unit,,he had a bunch of different odds and ends for sale and didn't seem to know much about the machine..