Beach bug

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It's late here,just finished looking over the Fisher gold bug schematic.
Very interesting indeed. Operates at 19.2 khz. Need to replace tx oscillator with something more conventional. Then do away with push retune and motion mode. Keep only automatic mode, eliminate battery test and change power supply to something more conventional. I like the receiver front end, only transistors. The auto mode is used 99.9 percent of the time so extra 4053 gate can be eliminated.
What do you guys think? The basis of a gold bug light? It can be called the beach bug.
Time for new project.

[6666]

There is a project here thats called Lobo light, it uses gold bug coils, could be worth a look

[6666]

I cannot edit my post so have to make a new post
Sounds like you are looking for a gold machine, Maybe its worth a look at this Lobo lite, from about post #204 onwards, look carefully at the coil info ,

PLEASE Note; the Lobo-Lite will only work with the Gold Bug, Gold Bug SE, Gold Bug DP, and Gold Bug Pro coils, or home built emulations of such, designed to operate around 19kHz.

It will NOT work with Gold Bug-2 coils (Gold Bug 11) which has an operating frequency of 71kHz, unless the filters and resonant caps are modified also.

I hope this is the post of interest, lobo LITE
http://www.geotech1.com/forums/showt...568#post170568

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yes, thanks for reply. You know I had a look at lobo but decided it was time to do something fresh that I could call my own work. It has to do with me ego you know, so I don't feel like old dinosaur.
So what I did was to have a look at the gold bug schematic and to do some improvements/mods to make it more agreeable for home brew project.
So heres the first step: Redraw schematic with different power supply and Tx section.

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I still need to enter the component values, but its the same values as gold bug schematic with the exception of the tx section(GC1018 tx Osc.) and power supply(which I hacked from GD1290). I am currently modelling the Tx oscillator to come up with appropriate component values for 20Khz because I want to use the TGSL coil since everyone is familiar with its constuction.
I also left out the two other modes since 99% of time only auto mode is used anyway. This avoids overcomplicated wiring and switches.

[dbanner]

Here is old video of gold bug where all features are discussed. Also note why two other modes can be dispensed with, they are not really needed.
https://youtu.be/H8GQD1Su0p0

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KT
I will be using KiCad for schematic capture and pcb design. I know this will be agreeable to you.
I will post schem file. Then you can help me design PCB?

[kt315]

agreeable. do it DB. i will help.

[Koala]

My vote would be to build it as is to start with. No motion mode is useful here in the uk if you want to search streams or woods. Plus the extra sensitivity of the motion mode.


Not sure how useful it will be as there no discrimination. But it time for a new project.


Shame the original GB2 schematics aren't available as it's still a desirable machine.

[dbanner]

My vote would be to build it as is to start with. No motion mode is useful here in the uk if you want to search streams or woods. Plus the extra sensitivity of the motion mode.


Not sure how useful it will be as there no discrimination. But it time for a new project.


Shame the original GB2 schematics aren't available as it's still a desirable machine.

There is no discrimination. I would have built the circuit unchanged but for the quartz and little transformer. That's why I changed only tx oscillator and phase shift. The power supply change presents no problem but not sure about the phases. Will need some help from members for that one to be sure.
Did you see the schematic I posted earlier in thread?

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I will include the motion/ no motion mode in final design, right now is for prototype to experiment with circuit to get things right.
They best part of this detector is its manual ground balance circuit for working in highly mineralized ground.

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If anyone knows coil data for original gold bug please post it here for me. thanks.