Baracuda broken

[Basti1983]

Hello my name is Sebastian and Iam 34 years old . I come from germany and I am new here.
But I already have a question about the Baracuda.

My problem is that I build yesterday the Baracuda Rev B 2.1 and it worked fine. I tried to fine tune it.But then a wire from the Batterie fall apart and came on the layerboard somewhere.
Now the Baracuda dont work. I still have the 5V and the -5V on the LF353 so i think that the 78L05 and the 79L05 work. Then I checked the 0V on the pin 6 (NE5534) but there was now 3V and when i try to adjust that it jumps from -volts to + volts i cant reach 0v anymore. Sometimes I can get a signal from the coil but I have to go so close to the coil. I am not so good in eletrical schematics but I can read values with my miltimeter and oszilloscope so I hope somebody can say me check this or that and it must be this value.

I hope your guys understand my english.

[Basti1983]

OK i checked now the power supply The 78L05 input 12v output 5V so this is ok. The IC7660 has input 12v output -12v goes into the 79l05 and it comes -5v so this is ok to. I am not sure for what the osc output is (7660) but there i have something with 8volts.So i think my power is ok and i have to go one and check other parts but there i need some help

[kt315]

5534 maybe fake. read similar subj http://www.geotech1.com/forums/showt...ackwards/page2

[waltr]

5534 could be fake if bought from ebay.
But, since the circuit seemed to work correctly before dropping the battery wire into the circuit I suspect that this blew out the 5534 and maybe other chips.
Been there and done that with lots of cursing then chip replacement.

The power circuits seem good.
I would pull all the chips out and use Ohmmeter and check for shorts.
Then put in the timing chips and test that the coil is pulsing and the sampling pulses are working. You really need an O'scope for this.
Then put NEW chips in one stage at a time and test each stage.

[Basti1983]

Ok thank you guys for your help.I ordered now new IC'S and replace them. I think too that the 5534 is blewed because the pot and the resistors for the circuit are ok. One more question i have. Has the Baracuda different beep sounds (high and low)?

PS O'scope i have

[waltr]

Hope that is all that is bad.

I only have Rev A schematics but pretty sure the changes to rev B are minor.
So, no, the only sound is at the PPS rate as described in the Build instruction.
Coil pulse go to Q4. U7b simply increases the amplitude, loudness, of the fixed audio tone.

One would need additional circuits (VCO) to create variable tones. Read through the other detector threads for ideas.

[Qiaozhi]

Hope that is all that is bad.

I only have Rev A schematics but pretty sure the changes to rev B are minor.
So, no, the only sound is at the PPS rate as described in the Build instruction.
Coil pulse go to Q4. U7b simply increases the amplitude, loudness, of the fixed audio tone.

One would need additional circuits (VCO) to create variable tones. Read through the other detector threads for ideas.

There are several problems associated with the original Baracuda which have been corrected in the Geotech Baracuda REV-A design.
Don't get confused between Baracuda REV-A, REV-B, or whatever versions. The Geotech Baracuda REV-A is the latest and most up-to-date revision.

Please read the introduction of the Build Document before you spend too much time on these legacy circuits.
http://www.geotech1.com/forums/showthread.php?23385-Geotech-Baracuda-REV-A-Project-Details

[waltr]

thanks Qiaozhi.
Those are the rev A schematics I have and refer to.

[BKY1337]

Hello, bad to hear that your Baracuda got damaged. Im the guy who sold you the Kit on ebay.
I can assure you that i only sent you good parts. I have built my Barracuda with the same parts, except the 7660 which was from Tayda-Electronics (12V max input).

I hope the guys here can help you with your problem.

What i would do is: Change all ICs. Then try it. If it wont work then change the transistors too.
But it should be possible to find the faulty part with measuring.

Its the Layout/schematic from kt315.

[Qiaozhi]

Hello, bad to hear that your Baracuda got damaged. Im the guy who sold you the Kit on ebay.
I can assure you that i only sent you good parts. I have built my Barracuda with the same parts, except the 7660 which was from Tayda-Electronics (12V max input).

I hope the guys here can help you with your problem.

What i would do is: Change all ICs. Then try it. If it wont work then change the transistors too.
But it should be possible to find the faulty part with measuring.

Its the Layout/schematic from kt315.

[ATTACH]42343[/ATTACH]

The schematic shown in your attachment contains the design errors described in points 1, 2, 4 and 5 in the Introduction of the Build Document.

[BKY1337]

Yes, but this is not the problem. The Layout is working.

I had 25cm with a Euro and a 15cm Coil. Do you think i can double this depht with Georges Mod?

[kt315]

to the depth George's mod does not have relation. George changed the connection of two resistors preventing burning out
of CMOS.

[Qiaozhi]

Yes, but this is not the problem. The Layout is working.

I had 25cm with a Euro and a 15cm Coil. Do you think i can double this depht with Georges Mod?

The pullup resistor mod will have a big effect on the depth. Also (if you don't make all the changes indicated in points 1, 2, 4 and 5) it will only be a matter of time before it stops working due to stress on the 7660A voltage converter.

[BKY1337]

I have a LT1054 mounted.

[6666]

The pullup resistor mod will have a big effect on the depth.