King Cobra PCB

[kt315]

try move far the coil from o-scope and PC - hang up on window like me I did. try to exchange TX wires connection in the coil. I did such way and now it works more stabile.
on photo Hot Head coil I opened - strange connection I did see and I remade this in more logical way, there one wire in cable was not used.

[kt315]

just now got nice 3pcs housing I bought from ukrainian seller.

[herpes]

hello, how are the data for the coil?, and there is indeed a resistor in it.

[calebsone]

ok i have an issue do you think the older tesoro coils have a different wire schem then the one previously posted i have 4 wires 3 used red green white and drain the red and drain i put on tx green white rx all im getting is constant tone in all met mode. all voltage is correct o-scope looks right im sure the coil is the problem. i tried reversing all connections but still nothing

[kt315]

can you measure resistances and inductivity of the coil? can you give pics of signals on TX winding and on preamp output? a trouble nobody did open old tesoro coils, no info besides some data Carl posted.

[kt315]

RX

[kt315]

TX

[calebsone]

sorry it took so long ok the detector works not like it should tho. the only thing i did that i dont see anyone else did is i found a 12v battery pack with a charger built in on ebay could it be causing all the noise i see on the oscope. im trying to get oscope pics up have to wait for my wife to give me the good camera

[herpes]

arrg, no wonder it does not work properly with me I have 6.5 rx - tx 6

[kt315]

4th unused wire now connected. resistor in RX winding is 47 Ohm.

[herpes]

hello, how is the total resistance of the two coils in each case? and how thick is the wire?
greetings

[kt315]

I can tell about Hot Head I bought a detector with, it is 30,5 cm outer housing diameter, 28 cm is TX winding diameter. I have not original GMT coil. no data on original.
TX coil resistance is 25,2 Ohm, RX is 69,6 Ohm.

[kt315]

the wire is same for TX and RX, 0,29 mm diameter. good luck.

[bernte_one]

hello herpes

i think it would be easier to change tx and rx caps to get the right induction / frequency relation (shift)

why not present your project in detektorforum too?

next days i will start to assemble my king cobra

i have some older tesoro coils here also a concentric from the stingray i think it will fit good

kind regards

[kt315]

DIP8 SO8 board

bought at ebay and just received those adapter boards http://www.ebay.com/itm/180952961067...84.m1497.l2649
now can use NE5534 in SO8 and opamps from trash electronics PCB's.

good luck