Teknetics T2(chinese knock off) assembly/disasembly/taking apart

[nonkapo]

Here you'll find info how to take apart Teknetics T2 (Chinese knock off). I hope i post it in the proper thread.

ATTENTION, VERY IMPORTANT!!!
If you do this your warranty will void. The author do not bear any responsibility if you do something wrong, hurt your self or damage your equipment when you follow the instructions. You do this at your own risk. If you have no experience please go to the otorized workshop or technician.


1. Remove the volume potentiometer's knob by pulling it towards you. You can carefully use fork to do that trying to not scratch the box.

2. To open the battery and dc-dc block you must unscrew three Philips head screws (1,2,3) and the plastic cover will get open. If you need the control box dis-attached, pull down the foam cover of the handle and remove hidden screw number 8. If you need the handle to be removed continue with hidden screws 9,10 and bolts 11 & 12. The elbow support can be removed only after the battery/DC-DC box and unscrewing 13 and 14.
3. To open the control box you must first clean the screw holes from the hotglue seal and than unscrew four Philips head screws (4,5,6,7). After removing the back cover the pcb will get exposed from the components side. To gain access to the back side of the board you must remove the settings knob, peel a bit the front panel decorative sticker and unscrew the settings vallcoder lock nut(i did not do this part so not 100 percent sure).

Assembly is reverse to the disassembly.

[nonkapo]

Here are the pics of the component side of the pcboard, dc-dc converter, connectors and the chips description. Photos of the ic's are not needed as they are visible well on the board.


MSP430F169 -16Bit Ultra low power MCU;

74HC4053D - triple single-pole double-throw analog switch;


TLE2426 - Rail splitter precision virtual ground;

LP2951 - Adjustable micropower voltage regulator;

LM393A - Dual differential comparator

[nonkapo]

There seem to be something wrong with my multimeter. First are the resistances measured with it. Second by the induction tester.

Multimeter:

1-2 - 42.2 Ohm(second example - 28.4 Ohm);
2-3 - Not connected;
3-4 - 5.1 Ohm(second example - 4.5 Ohm);
4-5 - 4.1 Ohm(second example - 3.6 Ohm);
3-5 - 4.1 Ohm(second example - 3.6 Ohm).

Tester:

1-2 - 39.2 Ohm(second example - 25.8 Ohm) - no inductance present?!?!?;
2-3 - Not connected;
3-4 - 2.6 Ohm(second example - 1.9 Ohm) - 0.72mH(0.66mH);
4-5 - 1.4 Ohm(second example - 1 Ohm) - 0.2mH(0.2mH);
3-5 - 1.4 Ohm(second example - 1 Ohm) - 0.2mH(0.2mH).

As i have two fake t2 coils, you can clearly see what kind of big tolerance is there.

[Skippy]

I think the Pin_1 - Pin_2 inductance is the same as the Fisher F75 coil, 6.95 - 7.00 mH

Pin_3 - Pin_4 is the transmit coil, it is centre-tapped , the tapping is pin_5.
In theory, the inductance of the total winding should be 4 times the inductance of each half. But theory doesn't work here. When you measure 'half-a-coil', the other half of the windings are still there, and they affect the measured value. I guess they are produced by winding 'bifilar' , that is, two wires would together, rather than "wind half, bring out a tap, wind the other half.".

MD Hunter has a T2 stripdown, which is worth adding to this thread:
https://md-hunter.com/opening-the-te...ew/#more-12713

[chesters4]

How easy was it to get the face plate off to expose the nut on the potentiometer i was afraid to touch it incase i damaged it but it would have been far easier that way.
The liberal use of hot glue i see holding the matrix in!

Sorry its not your pictures whoops

[nonkapo]

How easy was it to get the face plate off to expose the nut on the potentiometer i was afraid to touch it incase i damaged it but it would have been far easier that way.
The liberal use of hot glue i see holding the matrix in!

Sorry its not your pictures whoops

As i mention in my first post i was afraid to go that far,so just express the feeling i have about how you can continue. Just for the record as per me that's a val-coder which looks like potentiometer but work different way.

[nonkapo]

Some impressions after few months use and the delivery of the original coils.
The things go not as expected. The Fake T2 behave erroneously even with the original coils. When i bought the last one i come to know there are fake 5inch and 15 inch coils. Hope not my case, but before i have a hand on original T2 unit i cant say. So the coils tested are 5 inch stock, 6x10 inch accessory, 15 inch accessory, Detech 10x5 inch. I do not find affordable original 11inches one. The machine have issues with the ground balance even in clear from interference and trash areas. It is noisy and the threshold does not make it much better. Most of the time i have difficulties recognizing the target signal. This is for now my experience. Additionally all three units i check give continuous overload alarm with the 6x10 inch accessory. I get suspicious about the coil it self(second hand looking as new), but as no access to real T2 cant confirm. After several days trying different settings i manage to make it work on F7 and one of the three units work with it even on F5, F6, but any small metal object within short distance throw it immediately in to overload alarm(this on sensitivity 1 and threshold -min). Heard of damp coil triggering the alarm but in my case at least it works at some settings.

Finally the differences between the original T2 and Fake one which will be continued in case i found more. This article is for those who buy new units pretending to be original.

T2 original - grey menu button - Fake - old revisions red menu button, but newer fake revisions have grey too(so no warranty here);
T2 original - when turning the dial, sensitivity increases clockwise - Fake - increases anticlockwise;
T2 original - stiff shaft with the coil not wiggling much when searching - Fake shaft - wiggle like fat a..(especially with 11 inch and 15 inch coils). Fixed this replacing the shaft with section of stream fishing rod;
T2 original - when switched on it shows the serial/or software revision(may be only the newer units) - Fake - just gets powered on.
T2 original - Menu+trigger pinpointer hold during switching on must be factory reset - Fake - displays some software revision until release.
T2 original PCB - have different marks/date of manufacturing and socket for reprogramming - Fake have only holes for the socket but it is not soldered.
T2 original coil capacitor box is sealed nicely and evenly where some of the fakes cant reproduce that. Aditionally most of the fake coil sockets are not covered by termo-shrinking tube(however some of the original are not covered too).
The fake screw holes are sealed with hot silicone glue - don't know how it is on the original. Fakes may have paper printed serial numbers on the coil and the detector as well as ugly holographic stickers with the American flag and T2.

TBC and please feel free to add other hints to recognize the fake units or correct me if i mislead.

Good luck