EE Treasure Hunter prob

[christopher]

hi im from south africa and i built the first mark stuart EE Treasure Hunter but i am having problems with the pcb it seems that i cant get the voltage any higher than 9v (battery supply) it is supposed to be 16v after the voltage converter. i get no sound through the earphones at all. all the components are correct and i have checked the circuit over and over and everything is the same as the circuit diagram on your web site. maybe you can help me please. if you know of any changes to the circuit diagram or may be im doing something wrong.

thank you
christopher

[Nagan]

Hi,
I have made this one and it works.
However as far as i remember (and i have made it long time ago) there was some bugs in the pcb layout (2 or 3 bugs).
Try to compare the pcb project with circuit diagram and correct the pcb.
And the bugs was related to power supply from what i can recall.

Good luck,

[grimpo]

thanks

I have checked the cerkit and found 1 bug that was on one of the ic's but i still get nothing. I found if i lift one of the legs on c3 witch is a smoothing cap then i get an ajustable pulse sound through the headphones but when i conect the coil the sound goes crazy and no ajustment. Im going to keep looking.

thanks
chris

[Fred]

I know wo bugs:
-The boosted supply transistors are inverted on the parts list.
-Pins 12 and 13 of 4011 ic should be shorted.

I use bc548/bc558 for all transistors.

Fred.

[ikarus.nu]

christopher here is a very good pcb

good luck

[Unregistered]

In order to resolve this problem you must proceed in this way: to replace R5 10K>R5 330K - R6 10M>R6 15M - C5 22pF>C5 10pF - C4 1n>C4 39pf does not depend on the transistors but from IC1 that does not oscillate well with the values of the circuit it originates them. Excuse my english

[Unregistered]

TwinLoop Seeker

In order to resolve this problem you must proceed in this way: to replace R5 10K>R5 330K - R6 10M>R6 15M - C5 22pF>C5 10pF - C4 1n>C4 39pf does not depend on the transistors but from IC1 that does not oscillate well with the values of the circuit it originates them. Excuse my english

THE Twin Loop Detetcor is nice if we replace the IC with LM318 and changing the circuitry around it to get a positive feedback for feed back, removing the caps etc, and using only a single coil. Some one should try for dual coil with LM318 or NE5524A

[Unregistered]

Twin Loop

THE Twin Loop Detetcor is nice if we replace the IC with LM318 and changing the circuitry around it to get a positive feedback for feed back, removing the caps etc, and using only a single coil. Some one should try for dual coil with LM318 or NE5524A

Why didnt they( Robert and David) use a capacitor at pin5 to ground ( Modulation Pin) for Ne555's ???

[Unregistered]

I'm unregistred "to risolve....." this is a single coil pulse MD

[amtech2005]

EE treasure Hunter prob

Both the twin loop and ee treasure hunter had schemetic errors. Pin 5 on the 555 chip which you are talking about is the voltage control for the comparator but it is not used , so they put a capacitor from pin5 to ground to reduce noise. The Twin loop is designed with two coils to cancel out interference. The EE treasure Hunter project has just one coil. I am looking for the correct schematics . I attached another schematic for reference from Garys Chemelec site. Its a PI with one or a two-coil configuration. Eugene

[Unregistered]

Hello amtech2005 excuse for my english, can you post here the best schematic circuit of single coil EE treasure hunter?

[Unregistered]

I have changed the transistors, I have mounted BC327 and BC337 boost OK. With the battery 9V I have 16-17 Volt. Good the sensibility. From the moment that I give current, it begins to work after little second ones. Excuse my english

[amtech2005]

EE Treasure Hunter prob

CHRISTOPHER AND UNREGISTERED HERE IS NEW UPDATED SCHEMATIC AND PCB FOR TREASURE HUNTER

I have changed the transistors, I have mounted BC327 and BC337 boost OK. With the battery 9V I have 16-17 Volt. Good the sensibility. From the moment that I give current, it begins to work after little second ones. Excuse my english

[Unregistered]

compliments!!!! you have made an optimal job!!!!!!
a question: why 2 amplifiers? (LM5524 and TL071)

[Unregistered]

5534 TL071