Barracuda.....update(2)

[Leto]

still non working

HI
Thank you Geo and Michael.
Michael: I verified the 7xL05 pinouts and as I see from here both are installed right (no mistake). Please download both datasheets!!
79l05 (gnd-in-out)
78l05(out-gnd-in)
To your list I would add:
C1 is missing but this can be easily installed off-board.
Have put 1M resistor and C8 on solder side..

Can not understand that power supply:confused: ...
ICL7660 Vout is at -11.7V
79L05 Vout (Vss) is at -2.5V ... Why use two negative converters in row???
78L05 Vout (Vdd) is regular +5V.... Should not be Vdd and Vss opposite (-5/+5V)??
NE5534 pin6 is at 4.5V and no pot no matter how much I turn it makes no difference... also constant 337hz from speaker - same as coil.
Almost forgot Geo:
Oscilator is working! at 337Hz completly stable. It's driving coil (measured with DMM) with 6.6V at 0.43A So at least this is working..
I have replaced 2N transistors with appropriate BFs.. Maybe I should use originals??
So this is sadly it ... Opened to any ideas .... Can someone figure out that power supp.
Is this working circuit at all??? :confused:

[Unregistered]

Hi,
Your 7660 sounds like it is working correctly if you have -11.7v out of it. That means the problem has to be with the 79l05 regulator. First, I would recheck and make sure it is wired correctly. If it is, then look again at the part number and verify that it is a 79l05 soldered in there. If it is, then I would unsolder the output leg of the regulator and pull it up out of the board. Measure the voltage on it. If it is still -2.5V, then replace it. If it is now reading -5V, then you have a problem elsewhere loading the output of the regulator. These 79L series regulators can only source 100ma so it wouldn't take much of a problem somewhere else to load it down and read low. That is most likely going to be your problem.
Good luck,
Boattow

[Unregistered]

Hi,
I just looked at the datasheet, the power supply schematic, the PCB layout, and your picture of your PCB. The negative supply circuit looks correct. I would double check to make sure the part is a 79l05 installed on the PCB and if so, pull the output leg out of the board so it is contacting nothing and measure the output. It will most likely read properly indicating that the power supply is working ok but your PCB had a problem elsewhere.
Good luck,
Boattow

[Leto]

79L05

Thank you boattow for your time..
I folowed your advice and guess what - bad 79L05, I replaced it and voltages now are +5/-5.
But detector is still not working.
I compared datasheets for original transistors and used BFs. There are some big differences - will order original 2N transistors (fet's) and try it...

..or maybe the hammer will finish the job.

[Geo]

Hi Leto.
1. First put R27 and R29 at a middle position. Then with the coil connecting and far from metallic objects regulate R28. Now how to regulate R28?? Connect a voltmeter (multimeter) at the output of NE5534 and regulate R28 so the voltmeter to read a voltage between 0.1....1V (0.5V is better). Now if you put an object near to coil you must see the reading of voltmeter to differ. If is ok go to next step. If not look around the NE5534.
2. Put the voltmeter at pin 2 of U4a. Now if you put an object near to coil you must see the reading of voltmeter to differ a little. Make the same with pin 3. Make the same with pin1. Now if you put an object near to coil you must see the reading of voltmeter to differ very much.
Because i suppose that the problem is between two first stages i stop here. Try it. We wait your news
Wishes

[Leto]

Burnt IC No. 2

Thanx Geo..
As I could not trim output of NE5534 I replaced it with new one.
Now I can trim voltage well to 0.5V.
Also frequency of coil now (after 79L05 replacement) is 673Hz
Frequency of pin10(U1) is 335Hz
Frequency of pin12(U1) is trimable with R27/R29 from 340Hz to 1kHz+ here the freq is bit unstable.
What should be appropiate frequency for the sample delay?
I try them all but still no detection at pin6 of NE5534.:confused:
Can not find any problems around this IC :confused: but maybe there is another damaged part there. I'm really not sure.

[Geo]

Hi Leto.The frequency of U1 must not vary with R27 and R29. You must have the same freq at pin4, pin10 and pin12. R27 and R29 varies only the delay of the sample not the frequency. Look around the U1 for the problem
Wishes

[Geo]

Leto what about Barracuda problems :confused: :confused: ?

[mbiondo]

Baracuda problems

Hello Geo,

I have been following this thread with great interest...thanks for your instructions - they are a big help in understanding the circuit. I do have a couple questions about your post on 1/11/07 below.

You suggest first, to read the voltage at Pin2 of U4a with metal near the coil. Then, "Make the same with pin 3". Are you saying that we should try to make Pin2 & Pin3 have the same voltage? Do we use R27 & R29 to get the same voltage on Pin2 & Pin3?

Next step you say: "Make the same with Pin1". Are you saying that if we get the voltage the same on Pin2 and Pin3, that Pin1 should have the same voltage, or is there some adjustment we must make to get Pin1 the same as Pin2 & Pin3?

Thank you Geo, sorry I am having hard time understanding.

Hi Leto.
2. Put the voltmeter at pin 2 of U4a. Now if you put an object near to coil you must see the reading of voltmeter to differ a little. Make the same with pin 3. Make the same with pin1. Now if you put an object near to coil you must see the reading of voltmeter to differ very much.
Because i suppose that the problem is between two first stages i stop here. Try it. We wait your news
Wishes

[Leto]

Barracuda disaster..

Thanks Geo in your interest..
Firstly I should say that oscillator works like everything is perfect.. If I connect 350mH coil (1ohm) circuit draws 0.240A and mosfet becoms little hot. When 550mH (3ohm) is connected circuit draws 0.145A.
On pin6 of NE5534 can't get any change (maybe -5mv) -> I guess something is wrong with timings but do not know what.
I tryed with 4584 - no difference.
I wired C9 as in shematic and as in PCB layout - no difference.

With R38 I can trim LF412 pin6 from -0.002V to 0.035V.
Also do not trust BF256c transistors to be right replacement for 2n5485.
Will order original transistors this week but will wait one more week for delivery.
Hammer is waiting..

[Geo]

Hello Geo,

You suggest first, to read the voltage at Pin2 of U4a with metal near the coil. Then, "Make the same with pin 3". Are you saying that we should try to make Pin2 & Pin3 have the same voltage?
No, i mean to measure the voltage at pin3 and if you place an object near the coil you will see the voltage to vary.

Do we use R27 & R29 to get the same voltage on Pin2 & Pin3?
No, it is sample delay. Set them at a midle position (for this time).

Next step you say: "Make the same with Pin1". Are you saying that if we get the voltage the same on Pin2 and Pin3, that Pin1 should have the same voltage, or is there some adjustment we must make to get Pin1 the same as Pin2 & Pin3?
Pin2 and Pin3 must have about the same voltage. Pin1 must have big variation when place an object near the coil.

Wishes

[Leto]

Barracuda shematic FAKE? ... or just bad karma?

I tried the circuit with original transistors ->
NOTHING
No signal increase at preamp...
Nothing from the speakers...
For sure I will not debug this circuit without dual channel scope to see the timings - I'm sure there is a problem with Hex Schmitt Trigger.

ALSO
There is no report on this whole forum that this circuit was made by someone before and that it worked according to posted shematic.? Hiding failures? We should make a thread with >>FAKE OR NOT FAKE?<< topic.

[Roberto]

Isso aconteceu comigo...

I tried the circuit with original transistors ->
NOTHING
No signal increase at preamp...
Nothing from the speakers...
For sure I will not debug this circuit without dual channel scope to see the timings - I'm sure there is a problem with Hex Schmitt Trigger.

ALSO
There is no report on this whole forum that this circuit was made by someone before and that it worked according to posted shematic.? Hiding failures? We should make a thread with >>FAKE OR NOT FAKE?<< topic.

MONTEI O BARRACUDA E ACONTECEU A MESMA COISA.


Roberto- Brazil. Português

[Leto]

another report

MONTEI O BARRACUDA E ACONTECEU A MESMA COISA.

translated by Google:
I MOUNTED THE BARRACUDA AND HAPPENED THE SAME THING.

[Geo]

Hi all.
When i will finish with TGS i will give the Barracuda a try to make it ready to work
Does anyone have constructed it successfully??
Regards