TGSL-Mini 100x70mm

[Nandor]

Hi, for the pot connections you have to see the schematic, it also had been written down many times.
Continuous voltage is because there is not enough minus voltage.

[BKY1337]

I think the connections are okay , because i checked the schematic.
I asked because this is an other version of the tgsl. It uses 100k Potentiometer and i wasnt sure about the connections.

If a transistor is faulty then i dont know why i had -7.3V without ICs.

I saw that the tone changed when i swapped a coin over the coils (not yet nulled). I hope its only a transtistor.

I think i could be possible too that a positive Voltage neutralizes the negative voltage to about 0.6V.

[BKY1337]

I removed all ics again and had -6,9v , then I saw that it's only -0.7v with LM833 and -0.9v with LF353 instead. I think the Problem must be there.
Its the Ic at the lower left corner.

[BKY1337]

I have negative voltage and steady Tone with LM358 (Audio). I have only one coil (tx) connected.
When I insert the second ic from the left I have only -2v.

I forgot that i wasnt sure about the orientation of the Diode at Pin2 LM358 . Battery Check.

Its connected in the other direction in my schematic. Can this cause the steady tone?

I think i used a 4V3 Zener.

[BKY1337]

Same Problem with Diode in other Direction. :-(

[BKY1337]

Output of LM358 is steady 6.7 V, no other ICs at the board only 4024 and LM358. Pin 5 is about 300mV and Pin 6 is -150mV.
What is normal? A few mV?

[Nandor]

My TGSL consumes 26.5mA steady and 29mA with detection. Are you sure thath the PCB is correct?

[BKY1337]

This wasn't my question. I mean the voltage at the last op Amp. I know that something must be wrong. Im not sure with this Layout but I have checked the schematic and the only difference was the wrong orientated Diode. I need to find out from where the high Input for the LM358 comes. But I need to know first what is the normal Input without tone. I think 300mV is too high. I have negative voltage at the other Input, is this normal or do I need 0V there.

It could be possible that I accidently connected two points together while soldering. Some holes are really small.

[Hyena]

Do you have that scope you tolt you told us will buy?

[BKY1337]

I have a DSO 150 yes. But i cannot adjust the thing at the right side of the screen. But it works.

But for what? I don't have OPamps at the board. Only Audio. Tx is oscillating.

[Toros]

I have a DSO 150 yes. But i cannot adjust the thing at the right side of the screen. But it works.

But for what? I don't have OPamps at the board. Only Audio. Tx is oscillating.

I looked at your .lay file once more. Minus 5 volts are divorced correctly. Occasionally, defective operational amplifiers occur. The operational amplifiers must be checked separately. I suggest you make this tester. It checks single, double and quadruple operating amplifiers. I think it is very useful.

https://www.elektormagazine.com/maga...r-200503/17928.
This scheme can be found in many places on the Internet. If you decide to do it, note that LF356 is mounted on the back of the board.

[Toros]

You write above that you use LM833. Which place in the scheme do you use it?

[BKY1337]

LM833 was int the lower left corner instead of the lf353. But it's not at the board at the Moment.
Thanks for the tester but I think my OPamps are okay. I think the input is the Problem. I tried to measure the output at my working edu Version and I had -6 V where I have +7 Volts with this board. Output of LM358.

I repeat that I have only 4024 and LM358 mounted and all parts are new.

[Hyena]

LM833 was int the lower left corner instead of the lf353. But it's not at the board at the Moment.
Thanks for the tester but I think my OPamps are okay. I think the input is the Problem. I tried to measure the output at my working edu Version and I had -6 V where I have +7 Volts with this board. Output of LM358.

I repeat that I have only 4024 and LM358 mounted and all parts are new.

working edu has also only 4024 and last lm 358?

[BKY1337]

No, Edu has all parts. But the 100 x 70mm has only 4024 and lm358. Because I had steady tone and I removed all ics and I tried it with only one ic to trace the wrong voltage.