Deal, or train wreck?

[Jim in Idaho]

Bought a Discovery TF-900, with a broken-off transmit coil, but in otherwise good condition, and a Discovery TF-1200. I'd bought an Arc-Geo Logger from the same guy about 3 weeks ago, and it works great. Because he wasn't sure how well the detectors operated, and was clearing out a bunch of stuff he said $100 shipped would be fine, so I jumped. Any Info anybody has on that TF-1200 would be much appreciated. I'd happily pay for a manual copy for it. After following Ivconic's thread about rebuilding the TF-900 (many thanks!), I may be able to repair the 900.
I've never even heard of the 1200. But the faceplate and controls looks identical. Any info appreciated.
Jim

[Carl-NC]

Never heard of the TF-1200 either. Did either come with a pipe tracer accessory?

[Jim in Idaho]

Never heard of the TF-1200 either. Did either come with a pipe tracer accessory?

Carl, he didn't mention a tracer attachment, nor did it show in the pictures. The controls and face on that 1200 are identical to the 900, excepting the model numbers. Apparently the guy who's estate he bought the items from was a serious prospector, or at least into the field of data logging to gain more depth and sensitivity. The guy I bought the items from is definitely not a prospector. I initially figured the 1200 was some sort of tracer unit. Pleasantly surprised to find out it may be an advanced version of the 900. Must not be many out there. I'm wondering if it may have been introduced shorty before Discovery went under.
Jim

[Carl-NC]

I visited Discovery not long before the last owner (Roy) died. The only things he was building were Bigfoot coils and the CS9000, which was a rebranded TF900 for CScope in England. At some point Roy may have made the TF1200 but I doubt it would be anything more than a minor tweak of the TF900. The 1200 TX coil should work on the 900 so you would be able to see if it is otherwise good.

[ivconic]

You're welcome!
Don't be "afraid" of such work.
I wondered myself if it would ever work for me.
That way of coupling the TX front end with the antenna,
it was a certain unknown to me and I was convinced that it would not work for me in the end.
But it ended up being much easier than I had hoped.
It worked very satisfactorily and now I have a correct and good copy of the original device.
The only detail (imho) that should be paid attention to is the torus ring, or the type of alloy it is made of.
The original is hard to find, but it is "soft iron" type so that narrowed down the selection.
In the end, the green torus turned out to be a good choice.
You didn't mention but I believe you have the original ring and everything else will be easy.
Just follow the instructions for winding the coils and it will work fine.

[ivconic]

It's hard to find details on the internet.
The information is sketchy, but it looks like Carl is right. It is probably the same device.
Here's something I did find:
https://www.metaldetectorsforgold.ne...nder-1200.html

[ivconic]

However, I notice one detail that is different!
TF900 is powered by 9v, 6 cell "AA" battery pack,
While the link mentions that the TF1200 is powered by 12v, 8 cell "AA" battery pack.
Is that a significant difference?
Would the TF900 also run on 12v without the risk of burning something?
Is there any performance gain with 12v?
These are interesting questions, worth considering.
It's all the more interesting to look at detailed pictures of the TF1200 pcb.
If there is any chance and conditions, I would ask you to take "macro" pictures and details on the pcb of the TF1200.
In the name of the device, "9(00)" and "12(00)" catch the eye!
Is it a coincidence or is such a nomenclature intentional?

[kt315]

I may be able to repair the 900.

hard job waits you. you have to take off both pcb from TX and RX antenna parts. dust and dirt penetrate at them. you need to cleen and cover by varnish,
for electronics protection, by the aerosole. seal the bushings by silicone at end of the job.

screw off the screews on connection of antenna ring. pull it out, turning itself. you HAVE TO PULL OFF THE RING before to do something.

[Jim in Idaho]

I visited Discovery not long before the last owner (Roy) died. The only things he was building were Bigfoot coils and the CS9000, which was a rebranded TF900 for CScope in England. At some point Roy may have made the TF1200 but I doubt it would be anything more than a minor tweak of the TF900. The 1200 TX coil should work on the 900 so you would be able to see if it is otherwise good.

Thanks, Carl. I'd thought I might be able to use the 1200 coil on the 900, and I'm glad to see you suggest that. All I was after in this was to end up with a backup for my TM-800 (TM-808 w/Cave). I'm getting into the Arc-Geo interest, so wanted a backup. The selector/on-off switch in my 808 is getting funky, too, so I've got some work to do.
Jim

[Jim in Idaho]

Ivconic, and KT315...many thanks. Once I get my hands on these, I will update, with pictures. I'm not an engineer, but was a radar tech in the Air Force, so have some electronics experience, but that was long ago. We'll see how things go. If the 900 works, using the 1200 transmit coil, I may just sell the 1200. I'm always up to my backside in prospecting and projects, so not really wanting another long project. I took another look at the pics the seller sent, and see the manual/auto switch on the 1200 appears broken. The rest of it looks like new.
Jim

[ivconic]

The only thing I'm interested in is the power supply.
Does the 1200 differ in that part from the 900 model.
Or can the 900 model work immediately on 12v.
I would just like to clarify that.
The need to introduce a new model called the "1200" and at the same time look exactly the same as the "900" model from the outside...
seems illogical to me, UNLESS there were some major modifications.
In this case, probably only about the power supply.
And maybe there are other modifications.
That is interesting to clarify.

[kt315]

i grasp 1200 is same like 900 and 1200 is just adwertising. TM-808 is different animal. it has another circuit than TF900.
CAVE mode is DISC-STATIC mode taken from Whites 5900 Di PRO SL. TM-808 is STATIC part from whole circuit of 5900 Di PRO SL.

[Skippy]

"If the 900 works, using the 1200 transmit coil, I may just sell the 1200"
I would be interested in the 1200. Having paricipated in Ivconic's repair, I think I stand a chance of making it work again. As I'm in the United Kingdom, there is the international shipping costs to factor into my 'economics', so you may fare better selling it on US eBay ....

[Jim in Idaho]

i grasp 1200 is same like 900 and 1200 is just adwertising. TM-808 is different animal. it has another circuit than TF900.
CAVE mode is DISC-STATIC mode taken from Whites 5900 Di PRO SL. TM-808 is STATIC part from whole circuit of 5900 Di PRO SL.

Only the early TM-808's had Cave mode. The ones with Cave mode were actually the TM-800, which is a virtual copy of the TF-900 is my understanding. As far as the 1200, who knows?
It may the only difference is the power supply as Ivconic suggested. I'll do some digging into it once it arrives, and we'll figure it out.
Jim

[Jim in Idaho]

The only thing I'm interested in is the power supply.
Does the 1200 differ in that part from the 900 model.
Or can the 900 model work immediately on 12v. T
I would just like to clarify that.
The need to introduce a new model called the "1200" and at the same time look exactly the same as the "900" model from the outside...
seems illogical to me, UNLESS there were some major modifications.
In this case, probably only about the power supply.
And maybe there are other modifications.
That is interesting to clarify.

It will be interesting to see if the early TM-808 (TM-800) battery packs fits into the 1200. Even if it does, it doesn't mean much as far as voltage goes. I don't know if the same pack that holds 4 'C' batteries could be made into a pack holding 8 'AA' batteries. From the looks of the 1200, and 900, the battery compartment looks the same.
Jim