TESORO GOLDEN SABRE

[nakky]

golden

Hi Ivconic,I have original coil 20 cm cc.I will bring it to you,than I can also have a look at you romain site and pick up a lot of romain coins.TGS with original coil and 1M over 4148 is also noisy,10M will reduce it.But with DD coil it is more noisy ,10M will also reduce it a litle.I think DD is very sensitive?Grt Nakky.

[ivconic]

JRC/NJM2068

I replaced LF353 with NJM2068, claimed to be lowdrop,low noise and high gain op-amp...
When switched ON.....no bleeping at all.In All metal mode and in Disc mode!
Both! Even when Sense is at max.
But i lost that "soft" sound like it was with LF353. Now it is sharp and consistent...strange!?
Depth is same as with LF353...Havent checked on the field yet, only in workshop...

No i dont think that LF353 was bad choice. I think that LF353 is proper choice, but i must have some other problem here and at the moment NJM2068 suits better here than LF353...??? But what???
I have feeling it has something to do with phase...or have great influence on phase. Cose i noticed certain differences on phase shift, between cases when LF353 is on pcb and case when NJM2068 is on pcb???
There should not be any differences theoretically? But there are?
Also i played with 5K1 at RX coil inputs...No differences from 6K8 to 3K3???
Than why the hell 5K1??? From 3K3 to 6K8 is bleeping all the time and depth remains the same....
But without resistors (RX coil directly connected to LF353 inputs) NO BLEEPING...but less depth too..???
It seems that only weak signals producing bleeps...strong signals NOT??
Huh!
I am waiting my friend to bring me much better scope...and later i will continue experiments...

[ApBerg]

Originally Posted by Qiaozhi
I have 4 original Tesoro coils. If you send me one of your PCBs populated with components, I'll investigate the problem for you. As they say, two minds are better than one. I will even pay the postage both ways! How's that for an offer?

For Ivica a problem, but Qiaozihi can give me a mail...

Best regards.

Ap

[ivconic]

Hi,
this is a simple test.

Have you 2x TL071CN from STmicro from not more than 5years old production ?

If so you can use them in place of LM308s and ear for differences.

Do that if you can and you'll restrict the field focusing on 308s or comparators.

I've used for test also TL071CN of above from ST and got no bleeping at all, at max sens, with all the coils I have. Only drawback is that you need recent parts from ST (others seem not so good don't know why... maybe input noise optimization on that) and a reduction of about 5% depth.

I'm using at now 2 original LM308s from national but have sometimes bleeping at max sens... so I turn pot at say 95% max.

Performances are really good.

Best regards,
Max

Actuallly all this started when i was about to put TL081a instead LM308 at the first time. All that bleepeing started than. Later when LM308H obtained...bleeping continued on 8 pcb's!? I checked those with 4 different coils - same!
I will look for TL071 and test with those...

[ivconic]

I have 4 original Tesoro coils. If you send me one of your PCBs populated with components, I'll investigate the problem for you. As they say, two minds are better than one. I will even pay the postage both ways! How's that for an offer?

Oh, if we are closer! Fact that my country is not member of EU means a lot.
That fact keep Serbia to far away from rest of Europe...on Mars!
Every single,small packet (even plain envelope) will cost damn money for me to send abroad! One my friend send me 3cd's from Holland and payed only 3 euros for that!? If i was about to send simillar to him, it would costed me over 30euros!!! I cant even send money via Western Union from Serbia....can only receive from abroad...goodbye E-Bay! So far this is "deep hole"..i cant escape from here at all. Looking forward, next few years, things to be settled and finally to we get chance to live like any normal people..Until that....only this internet left for us...
Best regards!!!

[ApBerg]

Polyester

Hi Max.

Look out : polyester can shrink, so for coils ?? epoxy is OK.

Succes.

Ap

[Max]

Have you tried using fibre glass? You can get this from somewhere like Halfords. Alternatively you can use Araldite Rapid or Araldite Instant, but it may be a tad expensive if you need a lot.
http://www.silmid.com/adhesives/araldite2000/index.asp

Hi,
I've used fiber-glass with epoxy... like in boat constructions or surfboards to have a solid but elastic layer of fiber-glass potted. Used also carbonium sheets under pressure with long last epoxy of similar kind... very rigid but can crack as glass.

But maybe you mean fiberglass resin (polyester type?)... no I never used it. I'll try.

When make coils I usually use epoxy compounds A&B components (resin+hardner) but this time I get this cheap 1Kg total and tryed... but last very long (maybe 6-7 days for full hardening still don't know).

Used also polistirene-based-glue but I was not happy with that thing... bad smell etc

I've used araldite just one time for coils on a BFO one some years ago... but a very few quantity; due to costs I think is not good for sealing coils.

Anyway, I'm doing my last 2 coils using sun-light for to accelerate process... cause UV and some heat will get it strong in less time... few days.

Old tricks.

Best regards,
Max

[Qiaozhi]

Hi Qiaozhi... what's your epoxy ???

I'm doing stuff with a slow epoxy or maybe is just B component slow... really boring. Have two coils under epoxy at now... and seems an infinite work... I think that in the time it takes make that way... I can build another 10 and seal with a fast (and less cheap...) epoxy stuff.

What you suggest ? Anything from Maplin or something ?

Kind regards,
Max

Have you tried using fibre glass? You can get this from somewhere like Halfords. Alternatively you can use Araldite Rapid or Araldite Instant, but it may be a tad expensive if you need a lot.

http://www.silmid.com/adhesives/araldite2000/index.asp

[Max]

I have 4 original Tesoro coils. If you send me one of your PCBs populated with components, I'll investigate the problem for you. As they say, two minds are better than one. I will even pay the postage both ways! How's that for an offer?

Hi Qiaozhi... what's your epoxy ???

I'm doing stuff with a slow epoxy or maybe is just B component slow... really boring. Have two coils under epoxy at now... and seems an infinite work... I think that in the time it takes make that way... I can build another 10 and seal with a fast (and less cheap...) epoxy stuff.

What you suggest ? Anything from Maplin or something ?

Kind regards,
Max

[Qiaozhi]

Guess what!? From now on i am using ADSL connection. Finally! Now i will be more often here and can spend more time...Just wait few more days me to setup everything right....

About TGSL;

Quiaozhi, yes you are right but i dont have original coil,

I performed few wild tests last few days trying to locate problem.

Problem is not in coil! I am sure. Problem is at first kop's at disc and gnd stage....But what? Oscilations....most probably!
I'll take a day or two to experiment and than post my notes...


Hysterezis! Yes, but i tried few mods without success..

Keep on trying!
Regards!

I have 4 original Tesoro coils. If you send me one of your PCBs populated with components, I'll investigate the problem for you. As they say, two minds are better than one. I will even pay the postage both ways! How's that for an offer?

[Max]

Good question! But i think they are original.
Problem is at kop's...only not sure what should be the problem, yet..

Hi,
this is a simple test.

Have you 2x TL071CN from STmicro from not more than 5years old production ?

If so you can use them in place of LM308s and ear for differences.

Do that if you can and you'll restrict the field focusing on 308s or comparators.

I've used for test also TL071CN of above from ST and got no bleeping at all, at max sens, with all the coils I have. Only drawback is that you need recent parts from ST (others seem not so good don't know why... maybe input noise optimization on that) and a reduction of about 5% depth.

I'm using at now 2 original LM308s from national but have sometimes bleeping at max sens... so I turn pot at say 95% max.

Performances are really good.

Best regards,
Max

[ivconic]

Good question! But i think they are original.
Problem is at kop's...only not sure what should be the problem, yet..

[Max]

Guess what!? From now on i am using ADSL connection. Finally! Now i will be more often here and can spend more time...Just wait few more days me to setup everything right....

About TGSL;

Quiaozhi, yes you are right but i dont have original coil,

I performed few wild tests last few days trying to locate problem.

Problem is not in coil! I am sure. Problem is at first kop's at disc and gnd stage....But what? Oscilations....most probably!
I'll take a day or two to experiment and than post my notes...


Hysterezis! Yes, but i tried few mods without success..

Keep on trying!
Regards!

Hi Ivconic,
about bleeping again... are your LM308 original parts ??? look at them very well, I showed here why... there are a lot of fake devices from Asia that are sold by e.g. shops cause also european dealerd sometimes are victims of frauds from that not serious asian dealers.

If they are original national or motorola etc parts ok fine... they will be good and produce less bleeping.

I think problem is related more to op. amps noise than fets... in my TGS happens just sometimes at max sens with original LM308s in place.

Best regards,
Max

[ivconic]

ADSL!!!

Guess what!? From now on i am using ADSL connection. Finally! Now i will be more often here and can spend more time...Just wait few more days me to setup everything right....

About TGSL;

Quiaozhi, yes you are right but i dont have original coil,

I performed few wild tests last few days trying to locate problem.

Problem is not in coil! I am sure. Problem is at first kop's at disc and gnd stage....But what? Oscilations....most probably!
I'll take a day or two to experiment and than post my notes...


Hysterezis! Yes, but i tried few mods without success..

Keep on trying!
Regards!

[Fred]

Thanks Qiaozhi!