RELIC HAWK

[ivconic]

Musketeer and Rh are very simillar. Thus Musketeer could be adopted as lite version of RH. Working frequncy is 7kHz and at RH iz 5kHz.
90% of designs are identical.
So...look at output stage, there are BC547C and BC557c with that unknown transistor.
Bulgarians did not deciphered it and than used BC337/327 combination on their Coinseeker 2 Pro.
Few days ago i got brand new Coinseeker 2Pro pcb with all components soldered. It is not working? Dead!? I tested it with original RH coil.Not oscillating. Power drain is 20mA? Nothing warm or burns. No oscillations....
Powers supply lines are ok. Everything seems to be good. Yet not working.
So...my doubts are still on those transistors....
It is obvious that ordinary BC547C and BC557C can work there as far as last (smt) transistor is properly choosen.
Instead using various other transistors and "push" this to work, i would rather rethink and decipher original smt transistor and find its eventual replacement.
I also had Musketeer Colt in the past. And RH. Also inspected those pcbs...nothing strange nothing from Mars. Yet...these handamades refusing to work!?
Sheesh!

[KingJL]

Max,
What are the physical dimensions of the 15mh inductor in the audio circuit? I am asking because I see some ferrite E-Core(s) on ebay. There are two different sizes and I'd like to know which one to get.
Thanks,
J. L. King

[nakky]

Eclipse,thanks,but I think its OK now.Grt Nakky.

[eclipse]

nakky i can't make more fotos because i sold the device long time ago. i bought eureka gold which turned to be child's toy for finding coins and nuggets under the carpet...
I do have coinseeker board, if you need tips i can check the things you need.

[Max]

Ferrite contains iron ,so even if properties are different from it it may work on regular soil but not on ferrite.
It alslo probably depends of ferrite properties.
Fred.

Hi,
you are right Fred. I see a phase shift that occours when I lower much the ferrite rods... so, we know any phase shift will give an useful signal...for the MD... and an audio response if strong enough.

My dubt is about TGS... I have mine handy and today tested again and again with same rod... and it ignores that ferrite so easy!

But I think RH is much more critical device, more powerful TX etc... I mean... a few fraction of degree of shift and you'll get the beep... probably TGS is more tolerant with that issue and thus the better ferrite ignoring cause need larger phase shift or nearest rod to get into troubles.

Do you agree ?

Kind regards,
Max

[Fred]

Ferrite contains iron ,so even if properties are different from it it may work on regular soil but not on ferrite.
It alslo probably depends of ferrite properties.
Fred.

[Max]

Hi,
I have good news... not that's all working absolutely ok but read...

I've changed the GEB pot for 10turns and then regulate it in disc mode to null ferrite... and works very nice... I can null in a way ferrite stick is ignored at 1cm from coil, no sound... nothing.

Same happens to iron. Then I could still hear small cracks when iron (hammer) and ferrite rod are at 15cm or more... but I think is problem of something that saturates etc...

Now I tested for all-metal trying to do the same, since now there's a 10turn thing...

I reduced sens at 70% and got similar results... though not really as when in disc mode, 2-3cm no sound... but less there's sound... BUT before was very worse ... much more than this.

The iron instead is detected from far, like copper or aluminium AS EXPECTED.

So seems GEB works... only problem is that device it's really more sensitive to ferrite when in all-metal... in a way I cannot null better than 5-6cm when put sens pot to maximum...

I think this could be a weakness in design and sure, if it is, owners of RH must know that in all-metal they get more false signals from soil, more easy.

I say this cause I saw TGS ignore ferrite just under the coil... but, sure, power is less in TGS... we must consider this too.

What do you think ?

Kind regards,
Max

[KingJL]

About disc, with knob fully CCW I get 124.4° as start and 303.6° at end.
With knob fully CW I get 248° at start and end is at 428°. This at one extreme of geb pot... is different from simulation ?

124 to 248 = 304 to 428 (really 60) when you take into account 180 phase shift from GEB. Now when shift 90 degrees to get center you have:
-30 to 214
Simulation results (adjusted for 180 difference between GEB and DISC and then 90 degree to center of gate):
GEB -12 to 7.5
DISC -30 to 210 @ -12 GEB, -43 to 228 @ 7.5 GEB

Regards,
J. L. King

[Max]

No dubt... it's pin1!

[nakky]

[Max]

Sorry Max, I had changed the asc before I sent to you. R9 in asc should be 10k. Check both ends of R9 NOT R5. Everything else is the same. Sorry for the mistake that I sent you!!!

Regards,
J. L. King

Hi,
no problems I saw it... changed to 10K.

Thanks again,
Max

[KingJL]

Check both ends of R5 in the asc schematic. That is equivalent to min/max (or max/min) of disc. Actually it is pretty slick ,the way they arrive at DISC delay.

Sorry Max, I had changed the asc before I sent to you. R9 in asc should be 10k. Check both ends of R9 NOT R5. Everything else is the same. Sorry for the mistake that I sent you!!!

Regards,
J. L. King

[Max]

I can't see it ,is it pin 5 or pin1 ?

Where the f goes ? now I think it's pin1 for me... but maybe not

if not... then is pin5.

It's not really a problem... let me explain:

if is pin5 then the input is at pin6 (inverting) and goes to 18K
if is pin1 then the input is at pin2 (inverting) and goes to 18K

both ways the comparator inside see 18K at its invertin pin... that's what we are looking for to say it's GEB related.

BTW, Fred is right, I agree on the 9 and notch.

Kind regards,
Max

[Fred]

I can't see it ,is it pin 5 or pin1 ?

Hi nakky
If you look carefully you will see the "9" of lm393 so you know the position.
You can also see the notch designed in white below the IC.
regards,
Fred.

[nakky]

I can't see it ,is it pin 5 or pin1 ?