Tgsl i put the lf353 reversed and now no sound

[Ozoz_xba]

The board was running well before and i tryed to change some opams when i put lf353 reversed on the board by mistake the dedektor got beeeeeeeeeeee(long) and lm7808 got very hot and now no sound on the board.i change all the chips and checked all the diodes and transistors on the board .all the things looks ok.lm7808 got 8 volt in output.i have 15khz on tx and rx but no sounds on the dedector.bd140 looks good(checked on the board).i regornized that had always 11v at speaker but no beep and now 11vdc was gone.8 ohm speaker.can anyone help me when i put reverse the lf353 where the problem should be???it doesnt beep one when i turn on at first anymore and dont work.
I have some lm358 and 393 ,and ca3240 istead of lf353but no 308..

I have tx on ohm 14ohm but the rx was 8ohm when i checked after the problem(really rx i dont remember get itso low ohm .maybe i will try to open then coil)it was made by 0.45 wire .but the coil worked well before.i remember that the ohm in my coil that i made before should be at last near tx 14ohm.but it is 7.3 ohm now..
It should be near as when i made the coil tx i arranged it by 15khz and when i made rx i put on tx and get 13.9khz before.so i think that the ohm should be near tx and rx..

[dbanner]

The board was running well before and i tryed to change some opams when i put lf353 reversed on the board by mistake the dedektor got beeeeeeeeeeee(long) and lm7808 got very hot and now no sound on the board.i change all the chips and checked all the diodes and transistors on the board .all the things looks ok.lm7808 got 8 volt in output.i have 15khz on tx and rx but no sounds on the dedector.bd140 looks good(checked on the board).i regornized that had always 11v at speaker but no beep and now 11vdc was gone.8 ohm speaker.can anyone help me when i put reverse the lf353 where the problem should be???it doesnt beep one when i turn on at first anymore and dont work.
I have some lm358 and 393 ,and ca3240 istead of lf353but no 308..

I have tx on ohm 14ohm but the rx was 8ohm when i checked after the problem(really rx i dont remember get itso low ohm .maybe i will try to open then coil)it was made by 0.45 wire .but the coil worked well before.i remember that the ohm in my coil that i made before should be at last near tx 14ohm.but it is 7.3 ohm now..
It should be near as when i made the coil tx i arranged it by 15khz and when i made rx i put on tx and get 13.9khz before.so i think that the ohm should be near tx and rx..

The resistance of the Rx is very low, maybe it has become degraded due to inserting the chip in reverse, causing a short of the rails across the coil. Anything close to 1A sustained current for a minute or two may degrade the coil.
The difference between -5V and 8V is 13V divided by 13 ohms is 1A. Perhaps inserting the chip in reverse somehow caused this condition to occur.

[waltr]

@Ozo, Is there -5v(-6.2)?
Is the TX oscillator running (with TX coil connected)?

If the coil changed resistance then as Dbanner said, probably over current in the coil caused turns to short.
Try rechecking the coil inductance. If you don't have an inductance meter then use the method in the TGSL 101 pdf that uses the TX oscillator and you measure frequency.

[Ozoz_xba]

@Ozo, Is there -5v(-6.2)?
Is the TX oscillator running (with TX coil connected)?

If the coil changed resistance then as Dbanner said, probably over current in the coil caused turns to short.
Try rechecking the coil inductance. If you don't have an inductance meter then use the method in the TGSL 101 pdf that uses the TX oscillator and you measure frequency.

Yes the oscilator is running as i mesured the frequency on tx 15khz,i have also the voltage -5v and 8 on the chips but the rx ohm is about 7.3ohm and tx at 13 ohm(working 15khz)rx may have a short circuit and wires arond it can get touched as i didnt left it at 7.3 ohm but at last was 13ohm.i will see first the frequency puting rx at tx(13.9khz) and after the nulling ,if there is a problem i will open the coil and isolate the wires if i can see it.
Thx for responding

[Ozoz_xba]

I checked the coil rx the frequency puting on rx is 13.9khz.and ohm 7.3 ,its a low ohm no short circuit on the wire as i opened it.tomorrow i will make another rx coil with the new wire and will.i also have problems with thechips.how should i check if they work or not with multimetre or should i build a board for that with leds?

[Ozoz_xba]

By the way my circuit without tx and rx take 155mA and with tx and rx damaged get 60mA,no beep when open the dedector,just 1 beep when i close it

[dbanner]

That's why I used the term "degraded", and not "shorted", when referring to the low resistance of the Rx coil. If you wound both coils using the same gauge wire, then the Rx should be closer to 13-14 ohms, just like the Tx, only slightly higher.
You have "degradation" of the enamel coating insulation throughout the coil, so there is some leakage of electrons through the degraded insulation. That's my theory to account for the low resistance. It is also possible, as Walter stated, that there could be a short between two wires rendering a portion of the coil "shorted out" Both these scenarios could account for low resistance.

The Tx coil must be connected to the circuit to generate the negative rail voltage, so the idle current of 155mA you mentioned is not valid.
60mA is more in the ball park.

That being said, the resistance of the Rx coil is important from the Q aspect as well as the optimum performance of the preamp.
Rewinding the Rx coil should solve your issues, but the resistance of the Rx should be around 20-23 ohms if using 0.30mm wire.
This is optimal parameter for the Rx coil with this detector.
Rule with these type of detectors is to use thicker wire for Tx (0.4-0.6) and thinner wire for Rx (0.30mm) for example.

[dbanner]

It would appear from the coil data for the stock tesoro coils for these detectors that the Tx and Rx have similar resistances.

In a DD coil, that would infer using the same gauge of wire for both Tx and Rx, in order to satisfy the parameters.

However in a concentric coil such as tesoro's factory coil, I'm not so sure if the gauges are the same.

In the TGSL build documents, 0.25mm (30AWG) is recommended for both DD and concentric.

The general rule I stated above applied to concentric design in stock factory coils of some other detector brands where they tend to use thicker wire for the Tx and relatively thin wire for the Rx. I can't say what is the case for the tesoro factory coil.

Here is the data where you will find the correct parameters of the tesoro coils, this is what I use as a reference.

[dbanner]

I must stress the importance of getting BOTH the required inductance and resistance of the coils to the prescribed parameters for the detector to function properly as was designed. Otherwise it will work poorly, or may not work at all!

If all this is old news to you then that's fine.

Hope you can get everything to work out well with your project.

[kt315]

By the way my circuit without tx and rx take 155mA and with tx and rx damaged get 60mA,no beep when open the dedector,just 1 beep when i close it

sorry but without coil this schematic does not produce negative voltage for normal work of it.
you must always keeping the connect the board to TX coil.

pleasure
Anatloy

[Ozoz_xba]

sorry but without coil this schematic does not produce negative voltage for normal work of it.
you must always keeping the connect the board to TX coil.

pleasure
Anatloy

I got the -6v now it was becouse of diodes and i changed it.good news now.i have made an simple circuit to test the chips inverting input noninverting input and output and from 7 chips that o tested 2 of lm393 and 1 of lm358p doesnt gave an output in voltage(with led),i will check for lm308 and first change the damaged chips after will make a coil.thanks for your supports guy.

By the way should i use a fuse on the battery?500mA for example?

[kt315]

op amps of any sort are checking by esspecially projected OP AMP AND COMPARATOR TESTER. this is fastest way. just put op-amp and see on LEDs.
certainly i can not tell about it in every thread but everyone has a right to know. https://www.youtube.com/watch?v=-N5b8-TjuYk

[Ozoz_xba]

Thanks to k315 and the others.good news guys. I repaired my card,i had lf353 ,and 2 lm358 and 2 of lm308 burn,i tested all my new chips and put the one that worked ,just found a coil and tested the circuit.now the circuit work good.i put a fuse 315mA .without sound the circuit take 20mA and with sound take about 30-40mA current.i think that it is good.tomorrow i will make an DD new coil for it also will repair my concetric coil making it new.
Thanks guys for your helps and advices