TESORO GOLDEN SABRE

[nelson]

Hi Max.
Yesterday i got TL081 to replace LM308.
All other components are ok.
Now i hope i have the time to finish my MD this weekend.
When i get ready i ll post my results.
Regards and thanks.
Nelson

Hi Nelson,
plvr is right on single op amp...use lf356 or lf357 instead of LM308 and you would be ok. Use tl082 or others to replace lf353 that are dual.

Best regards,
Max

[Unregistered]

To nelson

Hi,
I can wate to see the results!I have ordered the same arangemend!
So,cant wait to here from you.I will have to wate more than week for my parts!
Nice job you put it together fast!!

[nelson]

Hi, yes i think this is the boring part when you have to cellect parts from here and there. But after that, the fun begans.
Regards and good luck with your project.
Nelson

Hi,
I can wate to see the results!I have ordered the same arangemend!
So,cant wait to here from you.I will have to wate more than week for my parts!
Nice job you put it together fast!!

[Unregistered]

Hello,
Thanks for your help!
Are you share that this will be equal replacement?

If you look at datasheetcatalog.com you no.

[Ultimate_Haze]

to Unregistred!!!

Hi,
I have looked!
I am woried because BF245C is marked as N-Channel RF Amplifier and PN4393 is N-Channel JFET Switch?????

I am beginer but isnt there a differance???
Thanks

[Unregistered]

helo

Can someone explain how I should conect switches and potentiometers?
I will be very hapy if finaly understand that!
Thanks

[Max]

Hi all,

Ultimate:
TL081 could be used too but is a bit noisy. I've tested in other circuits and sometimes you couldn't note any difference, sometimes you could very easy.
Depends on many factors. Anyway, if you have them just put in sockets and just see what happens.

About fets originals were TIS75 and I've found just 2 perfect replacement parts (obsolete USA made almost impossible to find):
2N5640
U1898E

The good news, as ivconic stated, is that for this project any small signal n-fet that suit the needs would be fine.

For BF245 replacement I think you could use any of these without problems:
BF244
MPF102
MPF112
2N3819
but take care that pinouts may differ from one type to another (and also on same type for different manifacturers--- so find the right datasheet first or test then in small circuit e.g. with a led or the like).

About
"I am woried because BF245C is marked as N-Channel RF Amplifier and PN4393 is N-Channel JFET Switch?????
"
OK depends on how it's intended to be used as default. What's important here is that bf245 is a N-channel fet for small signals and then could be used as switch too cause has a wider range of applications. PN4393 is (probably) intended to work as analog switch only and can't do exact same work of bf245 (e.g. radio-frequency mixers etc) without degrading performances. This is expecially true for hi-intercapacitance devices that can't be used in hi-freq applications.
Another good issue is current:
BF245 has 30V 10mA rating
PN4393 has 55V 50mA rating (so it's better for switching bigger currents due to construction , but have for sure much more intercapacitance(s)).

Keep going on. I'm interested too!

Best regards,
Max

[Hush]

Thanks a lot Ivconic for an answer! Now I can see some corections at
your schematic, and some more options. Beside that, I'll try to put a ground
balance at control table. TNX to kt-315, man from Mars too.
By the way, does anybody know where is Geo? Hope he's OK and somewhere
at holiday.
Now back on work- Golden Sabre and coils.

Oh! I'll need that eyeglasses!
Regards!

[nelson]

Hi Ivconic.
Today i finish tesoro golden sabre pcb with all components on it.
Just need to know how to connect swithches and potenciometers. can you draw it on the pcb to get a clearly idea?.
For 4.7uF caps i took two 10 uF electrolitics caps and solder the negative lead to each other. Then i place the positive leads on the board, but the value measure with my L/C meter II B, show 2 uF. Is this a problem?
For coil i ll make the same that you post.
Regards
Nelson

Here are pictures of my MD

Took another look at it, and...YES! KT315 is right! I traced pcb again.
Yes KT315 you are right! How i missed that!!!??? I have few different
schematics here....I payed attention on wrong one...Shhheeeeeesh!!!
Bravo KT315 and thank you!
But about loading resistor you mentioned...? I am not sure? Yes i can agree
with you, there must be loading resistor...but it is not there? And device is
working excellent!?
I corrected schematic and here is now; i really hope complete and accurate!
Porkluvr....Yes double O coil showed best results so far...but i gave up of those!
Why? I am gonna explain why; not so suitable on terrains i've been visitng lately.
There are a lot of bush arround,tree roots all over arround, high density opsticles
and OO coil is not just suitable enough to approach to every spot;under some tree or
between some stones...when coinshooting. I do that mainly...coinshooting.
So i made hard compromise and switched back to DD (double D) coils, again...
Double D shape is much more suitable for that kind of prospecting than double O.
But if you prefer leveled terrains than i suggest you to make OO coil cose a bit
greather depth than DD coil.That was my only reason to leave OO coils for now...
No i didnt say "...no gnd connection on RX..." !? Yes there is gnd connection on RX!
Must be! But not at pcb. That's why i didnt draw gnd connection in schematic.Not to
confuse somebody who might decide to draw pcb according my schematic...Later should
scratch or cut that piece of pcb to correct mistake...
GND connection at RX should be made in coil.
Pay attention on cable lead which connect coil via R13 to pin 6 of U101a!That lead must
be connected to gnd in coil!
I am using cable with 3 separate leads and common shield. Shield and 1 lead are connected to
faraday cage at both coils...all togather in coil housing. The other 2 leads i am using for
TX and RX....Simple as that. No twisted pair effect,no hums,interferences...no false signals!
I experimented with any other combination and this one is best.
Nelson, no you can not use only 3 lead cable....Shield and 3 leads yes! It makes 4 leads at
the end.
LM308 is hard to replace...beleive me! Only replacement i would use is TL081a...
About Bipolars....i never used those. I connect 2 ordinary 10uF cpacitors like this;
+ -- + and used those instead...
No, Nelson...if you using TLxx1 no need to reroute pcb; pin to pin compatible...
About NE5532...i am not sure...why dont you try NE5534? I never tried it...
OK. Again there is (i hope) very correct schematic...at the end. Take another look.
If something wrong let me know...
Anybody migh have good will to draw pcb for it? One-sided,small...C'mon....

[nelson]

Hi Ivconic. About the coil, is this configuration ok?
Thanks
Nelson

Hi Ivconic.
Today i finish tesoro golden sabre pcb with all components on it.
Just need to know how to connect swithches and potenciometers. can you draw it on the pcb to get a clearly idea?.
For 4.7uF caps i took two 10 uF electrolitics caps and solder the negative lead to each other. Then i place the positive leads on the board, but the value measure with my L/C meter II B, show 2 uF. Is this a problem?
For coil i ll make the same that you post.
Regards
Nelson

Here are pictures of my MD

[ivconic]

?

? Should read 5uF...or close?
Maybe you used bad capacitors?
Coil seems to be proper wired...it should work fine!
regards!

[nelson]

Thanks Ivconic. Yes i measured caps with another instrument and gives me 5.4 uF.
Ivconic, sorry for this question, but, can you draw how to conect swithces and pots. I can see on your MD that you place on the panes 3 pots and 3 switches. I have 3 pots just pots, 3 switches (on/off). Can these work on this project or i need a pot than can turn on/off and also do the resistance job?
Regards and thanks
Nelson

? Should read 5uF...or close?
Maybe you used bad capacitors?
Coil seems to be proper wired...it should work fine!
regards!

[ivconic]

I'll try to prepare for tomorrow, if you are not in hurry...Dont have it prepared....I dont understand? It is so easy and clear..? Just obey schematic and trace pcb....For testing purposes you may omit "notch" and all arround it...Only disc./all metal switch is needed....Sens.pot and ON/Off switch...for disc and gnd may use trimmers while testing...
OK anyway i'll draw pic tomorrow...
Here is more details about coil...
regards

[ivconic]

....


O.K. I did it now...Maybe a bit sloppy, but important is that you understand
how to connect those.
I guess there must be some other way to connect those, depends of what kind
of switches you may find...I connected it like this, since i had those
switches.
Switch On/Off may remain single, not attached on any pot, or can be in same
housing with Sense pot....never mind...
I wouldnt suggest you to use pot. for GEB, just leave it as trimmer.Adjust it
well on the ground, not to produce false signals while fast swinging over gnd.
Or you may use some hot rock instead real ground....or ferrite...
Do not forget those jumpers...What else...?

[nelson]

Ivconic, many thanks for nice job you have done to help us with little knolegment of electronics.
Everything now is clear and tomorrow i ll connect those pots and swithces. I will also made the coil.
Excellent job and best regards.
Take care
Nelson

O.K. I did it now...Maybe a bit sloppy, but important is that you understand
how to connect those.
I guess there must be some other way to connect those, depends of what kind
of switches you may find...I connected it like this, since i had those
switches.
Switch On/Off may remain single, not attached on any pot, or can be in same
housing with Sense pot....never mind...
I wouldnt suggest you to use pot. for GEB, just leave it as trimmer.Adjust it
well on the ground, not to produce false signals while fast swinging over gnd.
Or you may use some hot rock instead real ground....or ferrite...
Do not forget those jumpers...What else...?