Baracuda broken

[Andi68]

So what is the schematic, with all the corrections?

[BKY1337]

This here is Rev-A with schematic -> http://www.geotech1.com/forums/showt...roject-Details

The Board from Basti1983 is Rev-B without corrections (Georges Mod).

[Qiaozhi]

These problems were discussed over 2 years ago when several members were unable to build a Baracuda that was reliable. Sometimes the detector would work for a short time, and then fail, while others worked for a bit longer.

The problems were eventually resolved around March 2016, starting here (from post #432 onwards) ->
http://www.geotech1.com/forums/showt...roblems/page18

Impulse sent me his non-working Baracuda board for analysis, which eventually resulted in the Geotech Baracuda REV-A.

[Andi68]

Is the design of kt315 wrong?

[Qiaozhi]

Is the design of kt315 wrong?

I think that kt315 may have incorporated the changes in his version, but you will have to ask him.

[BKY1337]

Sorry, the schematic what i had posted was old.

I think this is the newest from kt315.

bara_sch.pdf

But this has nothing to do with the problem here in the thread.
I hope he can fix it soon.

My Baracuda Rev-B works fine.

[Qiaozhi]

Sorry, the schematic what i had posted was old.

I think this is the newest from kt315.

[ATTACH]42353[/ATTACH]

But this has nothing to do with the problem here in the thread.
I hope he can fix it soon.

My Baracuda Rev-B works fine.

If that's the correct schematic, then the pullup resistors are connected to the wrong power rail, the smoothing capacitors on the power supplies are incorrectly connected, and the voltage converter is an ICL7660 (which cannot handle the supply voltage). All these issues are described in the Geotech REV-A Build Document.

I've attached the Geotech Baracuda REV-A schematic so that you can see the differences. I note that kt315 has added some additional features.

[kt315]

i wrote where to disconnect trace and connect to GND. it is not so hard to do.
also, set resistors values from George's schematic (look my BOM file).

[Andi68]

THx kt,its easy for me, but that is all to do??

What means R8, Type=R_V_0.25

[kt315]

i stay mouse cursor on the resistor. then pattern name is lighten =)

V - vertical type
0.25 - watt

[Andi68]

Oke

[Basti1983]

Ok today i got the new IC's and the Baracuda work. I changed the 7660 CPAZ to a 7660 ACPAZ. Now i try to get better results by tuning the pots. One question I have is about the coil is it better to isolate the coil with aluminiumfoil or not.
And what is different in the newest Baracuda Version?

[BKY1337]

Do you know which IC was damaged? Its better to use the LT1054 instead of a 7660.

Look at the first five Points in the PDF "Building the Geotech Barracuda). You can read there whats different in the Geotech Barracuda.

One Point is a LT 1054 (15V max Input) instead of a 7660 (10V input). Yours has 12V Input.

Some Resistors are different and also connected different. Called Georges Mod (you can get more depth if you do it).

A smaller electrolytic capacitor is used for the 6800uF. (You can go down to a 2200uF if you need more space in your enclosure)

Also a few other changes were made in the geotech barracuda. You should read the first five points at the beginning of the PDF.

A shielding is not necessary. If you want to shield your coil then do not isolate it. You need to make a faraday shield. You need to leave 1-2cm open, (do not wrap it all around the coil).
You also need to wrap a tape around the wires first to isolate the shield from the coil windings.

You can use mylar tape,aluminium foil or graphite spray to make a shield. But its not necessary for a PI Detector.

Im glad to hear that you got i working.

[Basti1983]

No i dont know which one was broken a replaced all four . Because i just paid 3€.

[kt315]

Is the design of kt315 wrong?

my design is not be wrong because it is SURE ACCURATE ONE-IN-ONE copy of original board.