Baracuda broken

[Koala]

I take it the FET is getting very hot. It should only be getting warm and can be run without a heat shield for testing. I would guess the problem is due to something around the 2n2222. Is it the right way round. There are several versions and some have to be inserted 180 degrees to the legend.

[BKY1337]

I can not adjust pin 6 to 0 Volts. It is at 4 Volts and i can only adjust it to about 3.6 Volts with a 12V Battery.
I can adjust it to 0 Volts with a 9 Volt Battery and i have 27-30 cm depht at a 1 euro coin with a full charged battery.

I dont know why the mosfet gets hot.
It maybe works when i connect the 12V to the Mosfet and use a 9V for the circuit, but i dont think that this is a good solution.

[BKY1337]

I have meant the osc. picture from my gate. Is it normal?

I have a problem with my dso , i can not adjust the level at the right side anymore.
But i saw that i have something similar like the picture in your video with coil and 9 Volts.
This Wave changes a lot when i connect 12V and a coil. I have repaired the mosfet holes and soldered it in.
I get Spikes , it was TP 2 i guess (left from U4).

It still works with 9V , not with 12V. Tx Wave looks like in the baracuda PDF.

[kt315]

guys

ask what o-scope pic you need.

[BKY1337]

I dont mean your picture. Thanks for it by the way, i will make it like this in the future.

I have meant the oscilloscope picture. I dont think that i can measure a signal at pin 8 U4 without connected coil or can i?

Now i try to measure all the pulses from the geotech Rev-A pdf.

[6666]

My picture is from the MPP pi project, but it shows about mounting mosfets on PCB pins

[BKY1337]

I need to buy parts first. Is the picture ok?

[kt315]

temporarely use TIP127, for only seeking the problem.

[6666]

I completely pulled out two through hole platings where the mosfet is.
Was not a good Idea to desolder the mosfet.

Here is the Signal from the gate of the Mosfet, with desoldered Mosfet.

[ATTACH]42475[/ATTACH]

I can not measure anything at pin8.

Sounds like your PCB needs some repairs, you should always mount mosfets, voltage regs etc on pcb pins , makes it very easy to remove or replace when required.

[BKY1337]

I completely pulled out two through hole platings where the mosfet is.
Was not a good Idea to desolder the mosfet.

Here is the Signal from the gate of the Mosfet, with desoldered Mosfet.



I can not measure anything at pin8.

[BKY1337]

This is TP2 (at the left from U4):

I cant get a signal from Pin8. Or im too stupid to measure it.

Measured without Coil and 12V.

EDIT: I just saw that i measured Pin14 , not Pin8 :-D

[BKY1337]

Can you tell me the settings which i need to use on my DSO?
It seems like i can not measure anything.

With or without coil? I can not use a coil with 12V because of the Mosfet.

[kt315]

give pic on U4 pin8.

[BKY1337]

I replaced the 78L05 and now i have +5V and -5V. But the problem is still present.

The Mosfet gets hot. I get a signal when i touch it without connected coil.

I think i should replace the ICs and the Mosfet.

I also have a signal now when i connect the coil and 12V Battery and i set the treshold pot a little bit over threshold.
This wasnt before. I hope the Mod was not the cause of this.

[BKY1337]

I already tried to use it in the other direction without success it didn't work in the wrong Direction.