RELIC HAWK

[Max]

Hi,
I took a look at some pictures kindly provided by eclipse ... still cannot figure out about "f" stuff... cause difficault to follow but I see interesting stuff.

...all double op amp ic are 27M7, that would be nice having too there

All interesting, I'll take a look for other details...

Kind regards,
Max

[Max]

Hi,
I found now the 91K... so it's right in schematic we have.

But why there are 910K resistors then ??? Different from our schematic.

I found 2 of 910K till now, we haven't in schematic.

Kind regards,
Max

[RufusGartz]

Relic Hawk Manual

Relic Hawk Manual (English) (2822 KB):

http://rapidshare.com/files/12781117...alEng.pdf.html

One of the few manuals not available on Minelab's website. Finally got around to scanning it in. No, I don't have a Relic Hawk Metal Detector but I do have the manual.

Rufus

[eclipse]

Max don't forget that this is musketeer, and RH should have some differences (i think), but overall is no less than 95.99 % equal schematic. Probably the bigger coil gives extra boost in depth and also the musket misses the LSM switch.
I sold the device, i would be more helpful if i had it but ...
There was a bidding on ML RH on ebay few days ago but i didnt win cos i had a vacation and was away from the internet
the bid was too low.

[nakky]

Hi Max,I read in the manual that the manual gb trimpot must by 10 turns.Grt Nakky.

[Fred]

Now i understand!

[KingJL]

Hi JL,
yes, you are absolutely right about phase. I've changed number of turns to get 5KHz before making such tests... now I read 4.973 Khz on oscillator.

Wire is 0.56mm resistance around 2.5ohm, turns I'm employing at TX are 45.

PS: can you post the .asc file of your simulation ? I'd like to watch at it...

Kind regards,
Max

Here is zip containing the asc file and screenshots of run with GB set at 10K and 0.1 ohm.

Regards,
J. L. King

[KingJL]

Relic Hawk Manual (English) (2822 KB):

http://rapidshare.com/files/12781117...alEng.pdf.html

One of the few manuals not available on Minelab's website. Finally got around to scanning it in. No, I don't have a Relic Hawk Metal Detector but I do have the manual.

Rufus

Rufus,
Many, many, many thanks!!

[Max]

Relic Hawk Manual (English) (2822 KB):

http://rapidshare.com/files/12781117...alEng.pdf.html

One of the few manuals not available on Minelab's website. Finally got around to scanning it in. No, I don't have a Relic Hawk Metal Detector but I do have the manual.

Rufus

Hi Rufus,
very good ! Now we got the manual...

It's important about GEB tuning and the like!

Thanks,
Max

[Max]

Max don't forget that this is musketeer, and RH should have some differences (i think), but overall is no less than 95.99 % equal schematic. Probably the bigger coil gives extra boost in depth and also the musket misses the LSM switch.
I sold the device, i would be more helpful if i had it but ...
There was a bidding on ML RH on ebay few days ago but i didnt win cos i had a vacation and was away from the internet
the bid was too low.

Hi,
dang... you miss the RH on ebay! I saw the last offer was low for the value of machine. You lose that bargain... anyway... we are doing good here... probably you'll get enough informations to build one at the end.

Yes, they are not the same stuff... I think the 910K resistors are employed to lower the gain of some particular stages that have the bad tendency to saturate easy. But probably more than 95% is the same schematic... I see many similar pieces in the picture.

The brown smt with no labels are the decoupling caps 100nF at op amps.

Thanks for posting that pictures... everything is useful.

Kind regards,
Max

[Max]

Hi Max,I read in the manual that the manual gb trimpot must by 10 turns.Grt Nakky.

Hi nakky,
yes, right... I suspected that but someone told me before it was multiturn stuff.

As I said... probably less than 1° difference and GEB will not work at all... I see that on my clone... change to phase is so critical that anything apart a multiturn pot will solve that when on soil.

Kind regards,
Max

[Max]

Here is zip containing the asc file and screenshots of run with GB set at 10K and 0.1 ohm.

Regards,
J. L. King

Hi JL,
many thanks... this save me lot of work. I wanna check for mistakes on timing... but so far I haven't spotted anything bad.

I will compare simulations with read values and let all you know.

Kind regards,
Max

[Max]

Hi,
that's what I'm looking for... in page 18 of manual you can read this...

so it was not my imagination: in all-metal they know was really hard to compensate for GEB!

I'll do like explained... lowering sens... but I see it hard to find the spot before mounting some real multiturn stuff...I have a common pot there at now...

Kind regards,
Max

[KingJL]

Hi,
I see device is not so critical about nulled voltage... could be also some volts at output of preamp... and it still work (on the bench) like when there's 100mV there but I don't know about exact phase shift required.

I belive this design is meant to have the coil slightly off of null. This is forced by the feed of the TX through the 4 Meg resistor. I believe (but not sure) that the RX coil is supposed to be nulled by viewing the output of the preamp. This would slightly bias the RX coil signal to provide a better S/N from the coil (never let it really be nulled to 0). This may ever so slightly also increase the area of the DD overlap, increasing the width RX field.

Regards,
J. L. King

[nakky]

Eclipse,can you make two better pictures from the total board,top and bottum side or can you trace the F line ?It is hard to do with this pictures.Grt Nakky.