TESORO GOLDEN SABRE

[eclipse]

The "sorded details" :
2N2222 transistor (connected to 4024 trough 1K) was not placed correctly on Ivconics board which I used to make my board. I remember a post saying it's reversed, but when I made the board I forgot to change the orientiation and when soldering I used only silk screen on the board for guideline.
All other transistors are fine (I'm using PN2222 and PN2907)
Signal of pin1 - 4024 after that appeared and this solved the problem with the power supply and the audio appeared.

I also find that I have reversed (again on-board problem) 1N4148 connected to 4V3, because I've changed the pcb design almost anywhere near capacitor so that the Wima caps can fit.
This fixed the problem with the "bump" on the TX and the amplitude.
After calibrating the scope i was able to read correct 16V Tx (which I first though it's 10V) then came up the fact that the freq reading is aslo wrong.
(Okay I want to know who played with the scope ?!..)
We can't do without mistakes could we ?

That's all, the device is audioble, shows signs of detecting metal.
Pin 7 shows square or sinus wave, square when the coils are far from nulled position, sinusoidal signal - when close to ajusted, and the amplitude goes way down when I get closer. It will be hard to null w/o having accurate multimeter, Ill try to borrow better than mine for a few days.
I doubt i can do with the scope with it's 5mV/Div, even if I use it x10 amplificatation, if I use it directly connected to Rx
The only way will be output of LF353, where the signal is stronger.

[simonbaker]

Please tell us what you did to solve each problem - Amplitude, bump, negative supply. We need the sordid details...

Glad it's humming!

-SB

[eclipse]

Hi,
are you sure it's 35uS the whole period of signal ? Cause if so you have about 28.5Khz frequency... about twice the expected of more than 14Khz...

Maybe you made wrong calculations at scope ??? Check that....

I told you... the recipe is correct and really accurate.

If you have also a bad wire... e.g. thinner than 30AWG you'll always get lowered frequency and not higher than the 14-15Khz expected.

Kind regards,
Max

The recepie is bullet proof.
Checked the scope, it was deviding the actual frequency by factor of 2.
Quick recalibration and test, aaa here we are thats more like it - 14.5 Khz.
All misteries solved in one day,
Thank you
I think I need a beer!
Cheers

[Max]

Aziz I am following the recepie for the former 255x137 and wire with thickness 0.28 (with varnish).
I don't have LC meter so I can't measure the inductance...
The first tried has 100 windings and no shielding yet, resulting in 35uS mesured on the o-scope = 28,5 Khz
The second tried has 105 widings and shielding ( yes its the Rx coil, which i connected as Tx), resulting in 38uS on the scope = 26.3 Khz
I checked the capacitors in parallel with the Tx, they are fine, they are just like the schematic.
--
The only thing I can think of is that I've been lied in the shop for wires

" Hey boss this guys wants 0.28 wire and we don't have such,
so lets sell him 0.2 wire labeled 0.28 ".

If this is the case i suppose the wire I have is close to 0.28 but less than that, perhaps 0.23-0.25 with the varnish. I don't know how many turns I will have to increase exactly,
I'll try with 121 - 122 for Tx and see how it goes.

Hi,
are you sure it's 35uS the whole period of signal ? Cause if so you have about 28.5Khz frequency... about twice the expected of more than 14Khz...

Maybe you made wrong calculations at scope ??? Check that....

I told you... the recipe is correct and really accurate.

If you have also a bad wire... e.g. thinner than 30AWG you'll always get lowered frequency and not higher than the 14-15Khz expected.

Kind regards,
Max

[Max]

I am armed now! Sharp and dangerous!

Ha, finally i got some oscilloscope, beer for everybody, on me!

First thing i tested is pin 7. on LF353 ...perfect sinus.
Collector of 2N2907 is giving almost perfect sinus? Right side is a bit distorted...
That was all for now, havent slept from yesterday. Will conitnue tomorrow.

Huh....

Hi,
well done ! I see it well!

Beers now!

On TX side some non linearity is about normal stuff... but not much of it... otherwise there could be troubles.

On rx, pin7 or preamp perfect sinus: yeah, you need that and it happens cause of the resonant tank connected to a fairly high input impedance of preamp... that's why it's so smooth thing.

Kind regards,
Max

[eclipse]

Aziz I am following the recepie for the former 255x137 and wire with thickness 0.28 (with varnish).
I don't have LC meter so I can't measure the inductance...
The first tried has 100 windings and no shielding yet, resulting in 35uS mesured on the o-scope = 28,5 Khz
The second tried has 105 widings and shielding ( yes its the Rx coil, which i connected as Tx), resulting in 38uS on the scope = 26.3 Khz
I checked the capacitors in parallel with the Tx, they are fine, they are just like the schematic.
--
The only thing I can think of is that I've been lied in the shop for wires

" Hey boss this guys wants 0.28 wire and we don't have such,
so lets sell him 0.2 wire labeled 0.28 ".

If this is the case i suppose the wire I have is close to 0.28 but less than that, perhaps 0.23-0.25 with the varnish. I don't know how many turns I will have to increase exactly,
I'll try with 121 - 122 for Tx and see how it goes.

[Aziz]

Uh sorry my mistake. It's 16 Vp-p here also, I'm too excited I suppose
Frequency is far from the real - even with 105 windings coil im at about the same frequency, ~38uS

Is the 105 windings related to a circle winding core? If the coils are bended to a D form, the inductivity of the coil decreases and thus the operating frequency increases.
Check this out!

Aziz

[eclipse]

Uh sorry my mistake. It's 16 Vp-p here also, I'm too excited I suppose
Frequency is far from the real - even with 105 windings coil im at about the same frequency, ~38uS

[ivconic]

Guys a BIG thanks! I am so glad that the TGS is now in operating mode!
The negative voltage is -6.27V, positive is +7.98V, Tx is exactly 10 Volts.
There is sound from the un-adjusted coil , and actually it does detects , constant signal without metal which stops when metal object approaches..
offcourse max distance - 15sm ...heh still adjustments of the coil should be made...
The fight continues whith the coil construction!

Ivonic, congrats on the great machine you got there, I hope it will last long and will adjust many many boards :P!

Thanks!

"...Tx is exactly 10 Volts..."

What do you mean by this? At my TGSL output is 16vPP...

[eclipse]

Guys a BIG thanks! I am so glad that the TGS is now in operating mode!
The negative voltage is -6.27V, positive is +7.98V, Tx is exactly 10 Volts.
There is sound from the un-adjusted coil , and actually it does detects , constant signal without metal which stops when metal object approaches..
offcourse max distance - 15sm ...heh still adjustments of the coil should be made...
The fight continues whith the coil construction!

Ivonic, congrats on the great machine you got there, I hope it will last long and will adjust many many boards :P!

[ivconic]

I am armed now! Sharp and dangerous!

Ha, finally i got some oscilloscope, beer for everybody, on me!

First thing i tested is pin 7. on LF353 ...perfect sinus.
Collector of 2N2907 is giving almost perfect sinus? Right side is a bit distorted...
That was all for now, havent slept from yesterday. Will conitnue tomorrow.

Huh....

[Max]

Thank you will, do it.
----
Amplitude and "bump" error are now fixed.
I have pure clean sinus wave at the Tx with ~9.5V amplitude
----
Still frequency and -5V mistery needs to be solved.

Hi,
check frequency at output pin of 4024, must be (osc freq )/2 ...so for 14.6Khz expect to find 7.3Khz there, I mean the point where the r9 and R10 are jointed.

If not check the 4024... check supply, check if input signal is there.

If signal is present there check the npn/pnp transistors there at voltage converter: a usual mistake is when using e.g. bc547/bc557 instead of 2n3904/2n3906 (or others american kind) cause have reversed C and E terminals... just turn 180° if so.

If still doesn't work and transistor are OK, check diodes polarity and orientation, same for capacitors then if needed.

At tx you ideally have twice vcc ... so 8x2 = 16Vpp sinus... but never happens... usually you get anything from 9 to 14V there... depending of Q etc

You'll solve the puzzle.

Kind regards,
Max

[eclipse]

Thank you will, do it.
----
Amplitude and "bump" error are now fixed.
I have pure clean sinus wave at the Tx with ~9.5V amplitude
----
Still frequency and -5V mistery needs to be solved.

Hello Eclipse.

I think you wrote you use plastic transistors, look for the e/b/c pins !

The coil you use, 100 windings is ok, ceck in the transmitter part the caps and the zener diode.

Regards.

[eclipse]

I will be entirely busy with the TGS today. Nothing else will do.
I have the 1K resistor installed.
Checked the power consumption - it's 19mA.
On the point -5V i get only -0.8V, not good - any ideas? (dead diod ? or else smtg else)
I'm using MPS13 like the schematic
The windings are tight but not too tight, maybe this is the problem involved here. Ill try to avoid on next coil I'll make today.