TESORO GOLDEN SABRE

[Silver Dollar]

I had used OP07's instead of LM308's as the ones I bought were chinese imitations and
didn't work properly. Today I found some OP97's that are the same as the OP07's but
much lower power, reasonably good noise specs too! I'll change those out and try the
power to see how much current it draws.

The Bandito uses 15 ma and the TGSL was 30 when I started. I think the big 8v LDO
wastes 10 ma by itself and I probably saved a couple of mils with the OP97's so we
should be getting down near the Bandito spec...

[seadoggy]

I had used OP07's instead of LM308's as the ones I bought were chinese imitations and
didn't work properly. Today I found some OP97's that are the same as the OP07's but
much lower power, reasonably good noise specs too! I'll change those out and try the
power to see how much current it draws.

The Bandito uses 15 ma and the TGSL was 30 when I started. I think the big 8v LDO
wastes 10 ma by itself and I probably saved a couple of mils with the OP97's so we
should be getting down near the Bandito spec...

hi silver! so i can replace LM308 with OP07 on TGSL board??

[Silver Dollar]

Well the National Datasheet says:

Fits 725/108A/308A, 741, AD510 Sockets

Which I believe implies it can be used in place of the LM308.
I've used it in my TGSL but it has never worked perfectly so I
cannot say definitively. It has similar goals of stability...

[Silver Dollar]

I fired up the modified TGSL tonight. It draws 16 ma! That's approximately 1/2
of what it originally did. I lost depth though. The TX is only 10v P/P now though
on the Bandit that was plenty. I have been fighting a weak coil on it anyways but
still lost an inch or more so not sure if the OP97's are a viable option.

I'd like to find a low current strong oscillator for the original Tesoro coil. The minelab
style oscillator does a great job but requires a low resistance TX coil. It works on
a 6 ohm 2.4mh Tracker coil but not on the 20 ohm 6.1mh Tesoro. The Balanced H Bridge
does great too but it is trick to get the phasing pulses out of it without a bit of extra circuitry.

The new audio oscillator sound sweet too! It's a 430hz triangle and is smooth sounding compared
to the square wave original. You can make the original go deeper though as the narrow pulses can
sneak through the pulse filter and give a sound on deep stuff....

[sdesic]

I melted glue from my old "non working" coil and measured TX.
It is 5.75mH 25 Ohms.... as it should be 6mH
Maybe damaged from "melting" glue.

Can I use it with RX that I made new - 6.5mH and 25 Ohms ?

[Silver Dollar]

5.75 should be fine. If you look at the real original specs the TX's were a bit lower than shown here.
Just tune the TX for 14.7 khz or there abouts (by changing the small cap in the TX) and you should be
good to go!

I have successfully used a Tracker coil on my bandito. It uses 2.6mh TX AND 2.4mh RX...

[Silver Dollar]

Here's the chart;

Tesoro

Name TX-L TX-R (ohms) TX-fo TX wire RX-L RX-R (ohms) RX-fo RX wire Brown 8" 5.59mH 21.2 --- --- 6.23mH 22.1 --- --- White 8" 5.68mH 21.8 --- --- 6.36mH 22.8 --- --- White 4" 5.62mH 26.6 --- --- 6.13mH 28.2 --- --- uMax 9x8 5.74mH 24.6 --- --- 6.21mH 25.8 --- --- uMax 12x10 5.78mH 17.3 --- --- 6.15mH 18.9 --- --- Notice the TX Values

[sdesic]

It is OK to know that if I get one of those coils cheap.
15nF can be changed to 10nF or less
How do I calculate that value ?

[sdesic]

We are talking about TX and I am posting data on RX ... sorry
0,22 + 0,022F then

I was wondering about placing TX and RX coils in shell.
Is there any difference if TX and RX is switched ?
Or if TX and RX are placed wrong way - wound clockwise and placed differently.
Or if TX is lower or upper coil in shell ... as they are overlapping.

[Silver Dollar]

Coils can go any which way just swap the leads on RX if you get a double beep.
It's better for RX to be nearer to the ground (for better signal pickup).
For less noise it would be better if the outer wires were towards electrical ground.

I use this calculator to find cap values;
http://www.siversima.com/rf-calculat...FfB3cAodsAgAzg

[Koala]

"For less noise it would be better if the outer wires were towards electrical ground."

Makes sense. Something that had not occurred to me . Doubt it will make much difference but the sum of all little tips add up to make a greater difference.

[paku]

take much time
take many time
take ALL time to give stable on just one detectorist hahaha i hate that

[paku]

All My TGSl is default Part component only 4x 22uf replace with 4x 10uf now why my tgsl is only detect gold and copper not detect silver coin and euro coin

[paku]

now i setting the GB reject ferite i cant detect silver and coper but not detect gold ring
when i tune Disc to min i can detect gold and foil

Coil inductance
TX: 5.91mH Resistance 22.0 ohm
RX: 6.62mH Resistance 23.5 ohm

[sdesic]

now i setting the GB reject ferite i cant detect silver and coper but not detect gold ring
when i tune Disc to min i can detect gold and foil

Coil inductance
TX: 5.91mH Resistance 22.0 ohm
RX: 6.62mH Resistance 23.5 ohm

Are you shure it is gold?
Can you try gold coin?
Rings are difficult...