TESORO GOLDEN SABRE

[perdica 2]

if you can check caps in pikofarads and told their value

thanks for pictures

[simonbaker]

Here is schematic and component from early posts."W. Lahr" is not on this schematic, but I've looked at so many of these Tesoro schematics I think this is his work.
On component lay out only values I can see different are TL062 is LF442 and BF245 is TIS75 (like in schematic). Only one can not tell (yet) is Zener diode in Tx circuit. All the other values seem to be correct. The missing diode (4140) is on the bottom LM308 (on the schematic) I believe, the gnd bal circuit.

Will do more pains taking analysis of components, but no time right now, but Kurtie100 component layout and PCB from post #1 seem very accurate.

Also have to double check frequency for 8" coil as I think antenuation settings for counter may not have been correct.

Molzar

Thank you very much!

Regards

-SB

[perdica 2]

wrong schematic drawning R-3k3 from TX at disc-notch pot , at PSB picture 3k9

[simonbaker]

wrong schematic drawning R-3k3 from TX at disc-notch pot , at PSB picture 3k9

It's good to point out all these little differences, whether important or not. We should try to get an exact schematic of the real TGS. According to Molzar there is another 220 uF capacitor after the LM7808 not shown on the schematic also, as well as original parts. Let's get it right for the record. I wish we could help Molzar, but he has it to himself. Can do some work with the photos however.

Cheers,

-SB

[perdica 2]

i think this schematic is without any mustakes
need confirm from Molzar (for those cap`s in picofarads)

[Mullihaka]

Voltage symmetry, operational description?

Is the original TGS designed to have postive voltage at +8V and negative at -5V? I mean, would it harm if the negative voltage is increased (close to -8V) by slightly modifying the output circuitry of the 4024? Anybody tried that?

I have read all 125 pages of TSG messages, but couldn't find operational description for the TSG. While the main princible of operation is quite clear, I still can't figure out how the ground balancing, discrimination and notch circuitry work in detail. I guess they'll become self evident, when I build this device. I just have a bad habit of needing to understand what I'm doing.

All hints appreciated,

[simonbaker]

think this schematic is without any mustakes
need confirm from Molzar (for those cap`s in picofarads)

Good work!

But I think this schematic still has both diodes on LM308, while PCB apparently has only one?

Let's continue to verify it is exact as much as possible, just so we have an exact reference to the real Tesoro circuit. I tried to match front and back photos of PCB, but difficult to line up exactly due to distortions. I guess Molzar has the ball now...

Regards,

-SB

[Molzar]

Caps are correct. 3.3K is 3.9K. Diode on LM308 (GND Bal) not there, only other difference is 33k at last LM358, this is 2.2K.

Revised as per above.

Also note that manufacturer's "improve" (or substitute parts) design sometimes so some of these values maybe correct on earlier or later version of TGS.

Simon will try to make scan of pcb (may be difficult as standoffs are soldered to pcb) I Try.

Molzar

[simonbaker]

Caps are correct. 3.3K is 3.9K. Diode on LM308 (GND Bal) not there, only other difference is 33k at last LM358, this is 2.2K.

Revised as per above.

Also note that manufacturer's "improve" (or substitute parts) design sometimes so some of these values maybe correct on earlier or later version of TGS.

Simon will try to make scan of pcb (may be difficult as standoffs are soldered to pcb) I Try.

Molzar

Excellent! It increasingly confirms Ivconic's final TGSL design.

I'm sure it is difficult to get good scan of pcb. Perhaps you could try tripod with good digital camera mounted directly opposite pcb held in some kind of vice, exactly perpendicular and in center of camera frame. Try to move camera as far away as possible (3 to 5 feet or more), use maximum zoom. Then same thing for other side, exact same distance. Then maybe write on image any part numbers / values that are not visible.

Also interesting would be same pictures with bright light behind PCB to show shadow of other side at same time.

Just a little project to keep you busy!!! That is a lot of work, so of course we appreciate anything you can do.

On another subject: one mod that I think we should think about is a pot to control the TX oscillator amplitude. Ivconic just killed the feedback circuit to get max amplitude, and he gets best depth, maybe that is partly why. It seems like an important parameter, should be adjustable for us because we don't mass produce, we can tweak. Also need to experiment running oscillator directly off battery -- is it a good idea, or do we need very stable voltage?

Cheers!

-SB

[ivconic]

"...only other difference is 33k at last LM358, this is 2.2K...."

I was thinking about this many times in the past. 2K2 option is giving descent audio level and at the same time such treshold, enough to keep audio spikes almost calm. Sometimes, in some cases, when coil is not best suited and with 2K2, audio may have some chatters, reminds mostly on instabillity.
Yet, than 10K there will solve chatters problem but audio level would be decreased significantly. But if we adopt 33K as right value there, "stabillity" would be great and sound bairly audible...if any.
So i dont think 33K is possible value in any case.
I am rather prone to beleive that W.Lahr (if he put 33k on schematic) deciphered that resistor wrongly. It is not the rare case some resistor colours to dim in time, so most likelly 3 red "rings" on resistor could easilly look like 3 orange "rings" (red-red-red=2K2 and orange-orange-orange=33K).
So if man take skim look on resistor mounted on pcb, it is easy to be fooled by some colour changes due any objective reason.
My experience tells me that 2K2 resistor is right value there - original.

[ivconic]

"...Ivconic just killed the feedback circuit to get max amplitude..."

Actually i did that to get more space on my custom pcb...

TX already gets pretty stabille supply from 7808 via resistors. I made 20 and some TGSL's and noticed NO benefits or drawbacks either, from feedback circuit there (amplitude correctional stage - i would call it).
I havent met situation where TX amplitude tends to drift so far, at TGS/TGSL. So ... i am not using it anymore.

[grayfray]

golden sabre

Hello on this image, can anyone tell me which dial to adjust to calibrate a new coil, is it the top one or bottom one? thanks

[Molzar]

Bottom one is GND BAL, this is one to adjust coil.

Top one is for "Notch Width".

Looks nice...Good Luck!

Molzar

[grayfray]

reply

Bottom one is GND BAL, this is one to adjust coil.

Top one is for "Notch Width".

Looks nice...Good Luck!

Molzar

Thanks Molzar

do you have any instructions on re-calibrating a new coil?

[simonbaker]

"...only other difference is 33k at last LM358, this is 2.2K...."

I am rather prone to beleive that W.Lahr (if he put 33k on schematic) deciphered that resistor wrongly. It is not the rare case some resistor colours to dim in time, so most likelly 3 red "rings" on resistor could easilly look like 3 orange "rings" (red-red-red=2K2 and orange-orange-orange=33K).
So if man take skim look on resistor mounted on pcb, it is easy to be fooled by some colour changes due any objective reason...

Ah!