TESORO GOLDEN SABRE

[ivconic]

"..The funny thing is that disc works pretty good... and it cannot detect an hammer at 1cm in disc mode! .."
Same here! That is most funny, not only disc but geb also!?
Actually i stuck to damn pi 1. of LF353! Is it important to examine it after all?
Yes it si square ??? Yesterday was as you saw in shot, today with good cap from 100 to 330pf is square??? Differences between setup with 100pF and 330pf are only in purity of o.gramm not in shape!? Shape remains the very same from 150pF up to 330pF....
Today i'll replace LF353 with TL082,TL072,TL062 and simillars to compare...
About intermodulation...yes i think that too, but how to locate source of it?
When i solve that, automatically i will have chance to aplify audio more without risking of appearing false echoed beeps any more...
Now problem is completely "solved" with 18 and more ohms at the output...

[Max]

Max, GEo, ApBerg ...can you attach some 8 ohm speaker to your devices, turn Sense to maximum, Disc to minimum and test it on coin? Try to approach to coil with coin slowly just to start weak detection. Than remove coin slowly. Let's see is it gonna stop or continue with beeps...?
Also can you scope pin 1. of LF 353 and post shots here?
I am persistent on this. I will continue experimenting until whole thing become clear to me...

It stops on mine.

[ivconic]

"...otherwise it's a real boomerang..."
Most proper term for it!!!
Now when TGSL solved and working really good, if i add that resistor, i'll return this on the begining of problem...!?

[Max]

"..The funny thing is that disc works pretty good... and it cannot detect an hammer at 1cm in disc mode! .."
Same here! That is most funny, not only disc but geb also!?
Actually i stuck to damn pi 1. of LF353! Is it important to examine it after all?
Yes it si square ??? Yesterday was as you saw in shot, today with good cap from 100 to 330pf is square??? Differences between setup with 100pF and 330pf are only in purity of o.gramm not in shape!? Shape remains the very same from 150pF up to 330pF....
Today i'll replace LF353 with TL082,TL072,TL062 and simillars to compare...
About intermodulation...yes i think that too, but how to locate source of it?
When i solve that, automatically i will have chance to aplify audio more without risking of appearing false echoed beeps any more...
Now problem is completely "solved" with 18 and more ohms at the output...

Hi,
have you used the 10K resistor parallel to 100K pot of disc... cause I've made same simulations of porkluvr and results are the same... look.

I think you need it.

1. is the output at pin1 of 353 with the 10K (notch pot)
2. is the output at pin1 of 353 without the above pot...

Seems clear...

my problem is that I have the superimposed sinus WITH the notch pot there... that really puzzle me much.

Kind regards,
Max

[ivconic]

"...ONLY if there is already really rare and occasional noise..."

It seems there are some??? Fact that all bad things returned when 1M is present tell me that actually problem is not solved yet for real...
I am wandering what should be proper measuring points here on this TGS?
Can we establish those points and later scoping those we can eliminate part by part of device from further suspicion....With this method would be easy to locate problem and solve it.

[Max]

"...otherwise it's a real boomerang..."
Most proper term for it!!!
Now when TGSL solved and working really good, if i add that resistor, i'll return this on the begining of problem...!?

yes ... exactly what I felt when tryed the ST's TL071s there and found no bleeping anymore... then I switched the resistor to be there... and wow... it looked like a crazy horse again !

Damn thing !

Not to say what happens when I put the fake LM308s... it really sings and I have to run away from the lab !

Real boomerang if things aren't quiet... I suggest we put apart that mod till we solve all the "noise" issue.

Then after we (maybe) could rediscover that 1M resistor!

Kind regards,
Max

[ivconic]

Max i havent noticed any changes in behavior; with or without 10 K parallel to disc pot??? When it echoing beeps...it is doing that with and without 10k.
Also al other functions remained the same with and without 10K...It is not big deal, i'll put it again...But havent seen any changes....better or worse???

[Max]

"...ONLY if there is already really rare and occasional noise..."

It seems there are some??? Fact that all bad things returned when 1M is present tell me that actually problem is not solved yet for real...
I am wandering what should be proper measuring points here on this TGS?
Can we establish those points and later scoping those we can eliminate part by part of device from further suspicion....With this method would be easy to locate problem and solve it.

I think that good points are:

- collector of transistor at osc
- output of preamp (pin 7 353)
- output of "disc" amplifier (pin 1 353)
- geb syncro signal (pin 7 of 393)
- signal after 20K resistors (drain -or source- of that fets)
- output of first 2 integrators
- output of 308s
- output of comparators

But seems hard work trace them all...

What do you think ?

Best regards,
Max

[Max]

Max i havent noticed any changes in behavior; with or without 10 K parallel to disc pot??? When it echoing beeps...it is doing that with and without 10k.
Also al other functions remained the same with and without 10K...It is not big deal, i'll put it again...But havent seen any changes....better or worse???

Hi,
I think that you probably have some other and bigger problem that mask the positive effects of having it.

That's why you cannot see advantages... or maybe is just simulator that make us crazy now...

I told you I have dumped oscillations even with notch pot there ! that's strange thing for real: also for me having it or not is the same !

Maybe the LF353 is inaccurate ? Who knows... ?

What I know is that simulator tell me that I need the damn pot but then I see dumped oscillations on the "real" scope.

I guess the LF353 model that LTspice uses for simulation is too good to be real !

Best regards,
Max

[ivconic]

- collector of transistor at osc.....THIS ONE IS O.K.
- output of preamp (pin 7 353).....THIS ONE IS O.K.
- output of "disc" amplifier (pin 1 353)...STRANGE-SQUARE
- geb syncro signal (pin 7 of 393)....TO BE SCOPED
- signal after 20K resistors (drain -or source- of that fets)....SEEMS O.K.
- output of first 2 integrators....TO BE SCOPED
- output of 308s.....TO BE SCOPED
- output of comparators....TO BE SCOPED

So later i will scope all of those - sure no problem. I'll take shots.
You also take shots. We'll meet again here in few hours and compare...ok?
I'll be absent for 2 hours...be back than.
One more thing...yes i have same feeling that MPSA14 is draining to much power when "opened"...so i was thinking, only for experiment, to supply it through extra 7809 or simillar, incuding few filter capacitors...and than see what will happen? Of course in that case to strictly use 8 ohm spkr...
What do you think?

[Max]

Sorry, it's late... I've to go away now... let me know what do you think of points.

Best regards,
Max

[ivconic]

"...I think that you probably have some other and bigger problem that mask the positive effects of having it.

That's why you cannot see advantages... or maybe is just simulator that make us crazy now..."

Most likely i do!

But also possible other??? I never liked simulators...many times results from them do not correlate with reality!!! Plain truth!

[Max]

That's an idea... maybe it works... at least could reduce some problems.

But I think we have to understand LF353 behaviour too.

I cannot do scope traces this evening (cause I'll be not at home) maybe tomorrow... I need some time to trace and post all them.

huh ! I must go now !

Bye

[ivconic]

Bye!

[tiktak]

Hi

You can null using multimeter (I can too, I've tested and works cool) but be sure you gain exactly 0.0 mV not 0.1mV or something more or e.g. -0.1 ...cause otherwise you have maybe 20mVpp or more on coil and that's not so good.

1. without 1M mod for audio I get signal too but sound is weaker than with it... so I get e.g. 1eur coin at 34cm about loud without 1M resistor, with it I get with loud sound from 35-36cm too, that's about top of the range for it. That's more important with smaller stuff like small 1eur-cent coins , with 1M I get loud sound where I just cannot hear sound on speaker without cause is very weak. VERY WEAK BUT THERE IS ALWAYS... I mean if I use headphones I hear easy all small sounds I have without the 1M resistor.

2. I wound totally coil from start to finish from bottom (wood plane), and don't use separate layers... if you watch at my posted picture you will see that thing




Hi Max,
I think that you dont understand me for winding.I looked your pictures many times.I meen that if you make 100 windings on one layer you will recive much more diferent shape when winding is ready!Also did you wind TX and RX in same direction?
I have made stupid mistake again!! Yes 1K.Will try!
But have noticed that no mether what I try I hardly go above 24-25 cm on coin.
I will try null again with 1K and will tell you..
ABOUT TLC2262 I cant find this!
If I get you right this afect the behaviour of device iven if NOTCH is off right?
What is the distance that you reach for 10 euro cent coin?
I also noticed that my device is working sometime very good and other time its so noisy!
Thanks