TESORO GOLDEN SABRE

[simonbaker]

Unused 107b

Hi Ivconic, Max, and all:

My question is about U107b (half of LM358 for unused battery check).

Ivconic said to make connections as in schematic -- I think maybe to stop random oscillations or noise?

Do we really need all those resistors, or is there a simpler way to "deactivate" U107b, also with least amount of current drain?

What would be simplest, lowest power connections needed?

Regards

-SB

[simonbaker]

Hi Ivconic, Max, and all:

My question is about U107b (half of LM358 for unused battery check).

Ivconic said to make connections as in schematic -- I think maybe to stop random oscillations or noise?

Do we really need all those resistors, or is there a simpler way to "deactivate" U107b, also with least amount of current drain?

What would be simplest, lowest power connections needed?

Regards

-SB

A link I found about it:
http://www.maxim-ic.com/appnotes.cfm/an_pk/1957

Most TGSL schematics seem to have the u107b output driven low, which the above article says would consume extra power if it goes all way to rail.


-SB

[Max]

Hi Ivconic, Max, and all:

My question is about U107b (half of LM358 for unused battery check).

Ivconic said to make connections as in schematic -- I think maybe to stop random oscillations or noise?

Do we really need all those resistors, or is there a simpler way to "deactivate" U107b, also with least amount of current drain?

What would be simplest, lowest power connections needed?

Regards

-SB

It's not needed really... cause if someone wanna a battery checker can do much better using e.g. a led that glows when battery low etc

It's just a power drain... better avoid it, I don't like original design about it.

Sometimes is better pulling out fets...

Kind regards,
Max

[simonbaker]

It's not needed really... cause if someone wanna a battery checker can do much better using e.g. a led that glows when battery low etc

It's just a power drain... better avoid it, I don't like original design about it.

Sometimes is better pulling out fets...

Kind regards,
Max

Hi Max:

But I am asking about u107b which is there anyway, so shouldn't we put minimal connections to stop noise, oscillations, etc?

Regards,

-SB

[simonbaker]

audio stage

Hi Ivconic -

Referring to your "TGSL Final" schematic audio amplifier section:

1. Did you try using an MPSA13 or other Darlington in place of the two BC547 transistors? Or is there a good reason to have the two BC547?

2. Why is emitter of TR3 (BD140) connected to +V, instead of collector? The circuit seems very unusual, how did you decide on it?

Regards,

-SB

[Ultimate_Haze]

Hi,
Max.
I have try to adjust like you show.But I can see this relationship only in chop.Is this normal or my oscilloscope is not working properly?
I see that my TX signal have some distortion in peak.Can this be the source of my problems?
Here are some pictures:

[ivconic]

I think there is nothing wrong with your TX signal. I get exactly the same shape. That little notch is supposed to be there.
Is that 15vpp amplitude? I think it is. So you have very right signal at TX output. Good!
Cheers!

[ivconic]

Oh yes; take measuring from pin 7. of LF353 and post photo here...

[Ultimate_Haze]

Hi,
Ivconic.
Thanks for the fast reply!
So TX is ok.
I am shame but its my first steps with oscilloscope and still ALOT to learn.Plus I dont have manual for this.So how to understand what is my p-p voltage?
On second picture there is TX signal/collector 2907/ VS 353 pin7 this is in chop.Anyway I will make some more pictures.
But still my sensitivity is too low.
I have noticed before that there is a small diferance in voltages somewhere in RX section.I will check again and will give some more info.
Have a great day.

[Max]

Hi,
Max.
I have try to adjust like you show.But I can see this relationship only in chop.Is this normal or my oscilloscope is not working properly?
I see that my TX signal have some distortion in peak.Can this be the source of my problems?
Here are some pictures:

Hi,
the little notch, like Ivconic already stated, is just a small non-linearity at oscillator, mine is the same... are all about the same cause transistors aren't ideal devices... and small non-linear behaviour is normal.

Also, if you simulate in LTspice, as example, you get same shape with notch... cause transistor models are accurate and close to reality.

About chopper mode... you use it depending on frequency, in some cases alt mode is better to see the two signals but TGS runs at 14Khz and up (VLF, so very low frequency) so you'll be fine in chop mode with your scope.

Check the amplitude of signal at TX, must be 15 to little less than 16 V peak-to-peak , if so you have correctly running oscillator then will check other signal (rx one) for details.

Kind regards,
Max

[Max]

Hi,
Ivconic.
Thanks for the fast reply!
So TX is ok.
I am shame but its my first steps with oscilloscope and still ALOT to learn.Plus I dont have manual for this.So how to understand what is my p-p voltage?
On second picture there is TX signal/collector 2907/ VS 353 pin7 this is in chop.Anyway I will make some more pictures.
But still my sensitivity is too low.
I have noticed before that there is a small diferance in voltages somewhere in RX section.I will check again and will give some more info.
Have a great day.

Hi,
p-p, or peak-to-peak voltage is the vertical distance between positive and negative peaks (up to down or down to up peak).

You count squares and squares' divisions... then multiply by the V/div setting on the panel: that multiplication gives you the voltage p-p.

Kind regards,
Max

[Ultimate_Haze]

Hi,
Ok.Thats easy.As you can see on first picture for chanel one 16 X 0,5V=8Vp-p.
Its too low.
you say 14-16.
What could be the reason?

[Max]

Hi,
Ok.Thats easy.As you can see on first picture for chanel one 16 X 0,5V=8Vp-p.
Its too low.
you say 14-16.
What could be the reason?

Hi,
it's about 3 square height, the square value is 1, the 5 divisions on squares are 0.2 each, but you must consider your probe also:
if probe is 1:10 attenuated you must consider 10 times what you read on screen.

Now, if 1:1 you have (roughly) 3x0.5 = 1.5V (it's unreal you get such 1.5V)
but I suppose probe is set at 1:10 (attenuated 10 times) so you have actually 3x0.5x10 = 15V peak to peak

If so... 15Vpp are about close to "perfection"!

Kind regards,
Max

[Ultimate_Haze]

Hi,
My probe is X10.
So its OK.
First I tought that I should count the devisions and multiply.
Now its clear.
What next?

[simonbaker]

Hi,
Max.
I have try to adjust like you show.But I can see this relationship only in chop.Is this normal or my oscilloscope is not working properly?
I see that my TX signal have some distortion in peak.Can this be the source of my problems?
Here are some pictures:

If you used TGSL Final version of Ivconic's, you will have notch because there is no feedback-regulating JFET in oscillator. The benefit is you get larger voltage. With original circuit, you can get rid of notch by adjustments.

Regards,

-SB