Baracuda broken

[BKY1337]

kt315: My computer with your files is not working. I use my Laptop now. Can you please tell me the values of the resistors which i need to change (Georges Mod).

I tried a new coil today and i only had 20-25 cm with a euro. 25cm Coil. I wanna try this mod. I have the picture with the trace and the bridge but not the resistor values.

[Andi68]

For me, it has become a bit confusing because of the many contributions to the Baracuda.
And my english is bad ....
I will build the circuit but the next few months and see the result.

BKY
For George's/Qiaozhi mod change:
R18 12k
R19 15k

[kt315]

kt315: My computer with your files is not working. I use my Laptop now. Can you please tell me the values of the resistors which i need to change (Georges Mod).

I tried a new coil today and i only had 20-25 cm with a euro. 25cm Coil. I wanna try this mod. I have the picture with the trace and the bridge but not the resistor values.

BKY

you got from me Gerber files WITHOUT PAYMENT. FOR ABSOLUTELY FREE. NO ONE CENT YOU PAID ON MY FUTURE PROJECTS.

you are so tactless and ruthlessly rude men asking to consult you in on-line mode.
i will give you income statement list, you WILL SEE MY MONEY i get on my job. i must photoshoped some places.

[BKY1337]

Thanks Andi.

I tried my 380uH coil with my russian pirat and got the same result as with my barracuda legend. About 25cm with a Euro.
Unfortunately i can not detect a very thin goldring anymore. I could with my 15cm coil and i had almost the same depht with a euro.

I will change the resistors.

[BKY1337]

BKY

you got from me Gerber files WITHOUT PAYMENT. FOR ABSOLUTELY FREE. NO ONE CENT YOU PAID ON MY FUTURE PROJECTS.

you are so tactless and ruthlessly rude men asking to consult you in on-line mode.
i will give you income statement list, you WILL SEE MY MONEY i get on my job. i must photoshoped some places.

I dont know what you mean with this post.
Are you mad because i asked for the resistor values?

[kt315]

so hard to take the values from George's schematic?

[BKY1337]

so hard to take the values from George's schematic?

No, but i saw that you are online and i decided to ask you. Sorry for that.

I made the changes and i have more Sensititvity and more Depht. Changed from 25cm to 32cm for a Euro. I can detect a small Gold Ring now. I couldnt before.

The Detector is still not tuned properly. I still ned to adjust the Damping Resistor.

[Qiaozhi]

I made the changes and i have more Sensititvity and more Depht. Changed from 25cm to 32cm for a Euro. I can detect a small Gold Ring now. I couldnt before.

Well done. This shows that the mods are easy to do on KT315's board, and that they improve the performance.

[BKY1337]

Now i have a Problem with my Barracuda.
My battery became empty today 8x1,5V. So i know that it was almost empty when i had the 30-32cm yesterday.
So i decided to put new batteries in and the barracuda doesnt make a sound when i have the full 8x1,5V Batteries connected.
I saw that my IRF became extremely hot and the coil is humming. It wasnt before.

Its not damaged because i can connect a 9V Block Battery to it and it runs with about 20cm depht.

My parts are all safe up to 16V (15V LT1054), I changed the big capacitor to a 2200uF 16V. I have no clue whats the problem.

The batttery pack has 12,4V.

[waltr]

Now i have a Problem with my Barracuda.
My battery became empty today 8x1,5V. So i know that it was almost empty when i had the 30-32cm yesterday.
So i decided to put new batteries in and the barracuda doesnt make a sound when i have the full 8x1,5V Batteries connected.
I saw that my IRF became extremely hot and the coil is humming. It wasnt before.

Its not damaged because i can connect a 9V Block Battery to it and it runs with about 20cm depht.

My parts are all safe up to 16V (15V LT1054), I changed the big capacitor to a 2200uF 16V. I have no clue whats the problem.

The batttery pack has 12,4V.

Is the LT1054 output Voltage and all other Voltages correct?

Are the Timers working?
If the Coil MOSFET is not being properly turned On/OFF then it will get hot.
Is the MOSFET Gate switching properly?

[BKY1337]

I dont know how i should measure this because i dont want to destroy something. The Mosfet becomes hot very quick.
Can i measure it without coil?

I need to look where are the Pins first.

I could measure everything with 9 Volts , but i think everything works fine with 9 Volts. It did with about 10 Volts too, but not with 12.

I dont know if it worked before the Mod because i think that my battery had only 10 Volts when i built the board.

[waltr]

Yes, you can test without a coil connected. MOSFET should NOT even get warm, only current would be through the damping R.

Use your O'scope to check that ALL pulses are working properly with the correct timing.
The MOSFET gate should be switching to correct Voltage levels, 0V to +VB. Ensure the Base of the MOSFET Gate transistor is being switched.
The P-ch MOSFET's gate should be high (+VB) to be OFF and low (0V) for the TX pulse period.
+5 and -5 Voltages correct?
Oscillator running (U4)?

[Qiaozhi]

I dont know how i should measure this because i dont want to destroy something. The Mosfet becomes hot very quick.
Can i measure it without coil?

I need to look where are the Pins first.

I could measure everything with 9 Volts , but i think everything works fine with 9 Volts. It did with about 10 Volts too, but not with 12.

I dont know if it worked before the Mod because i think that my battery had only 10 Volts when i built the board.

The biasing of the MOSFET is such that it does not get stuck on if the oscillator fails. What's more likely is that the TX oscillator is affected in some way by the increased battery voltage. Perhaps you could test it using a bench power supply, and gradually increase the voltage to see what happens.

[BKY1337]

LT1054:

Pin8: V+ Battery 12V
Pin5: Vout -11,7V

I dont know what Pin7 is but i had 2,66kHz there.

Is this Output ok???

LF412:

Pin4: -4.98V
Pin8: 11,9V

Mosfet:

Gate: 0.71kHz
Damping Resistor is 330R
Mosfet is cold without Coil.

I have only a DSO150 , i fear that i can damge it with too high voltages.

[BKY1337]

I can measure 0.41 kHz at Pin 4 40106.

TP1 is 10V. I think i could connect it to my DSO.

Drain of 78L05 = 0Volts
Drain of 79L05 = -2.45Volts input is -11.7V from the LT1054 <---- Damaged?