BARACUDA-Legend-1

[bernte_one]

hello brian

seems that we all have to fight with unperfect produced parts time by time
if you replace the ic try another from a better brand
pay 10cent more and you have no trouble next time

since my beginning with detector diy i uses for example only metal film resistors 1% before mounting i measure them if the have to big tolerance i dont use them on detector maybe later for some led projects

can help you with your specific problem but soemtimes it was better for me touse a part from another brand

regards

[Brian Deese]

Barracuda acting up today

Now the other day I replaced the mosfet and the 2n2222 and had it running good,all the timing wave forms on the 40106 were clean and sharp square waves except for the cap charging pins which were sawtooth but all was good.It was detecting good enough to take to the field so I made the enclosure,pole,handle,put it all together.Got a new lipo battery and charger and all. Turned it on and it was dead as 4 oclock,40106 all pins flat no switching. 7066 working,both regs working fine.What the hell? So I began to doubt my new lipo battery,disconnected it,and reconnected the wall wart power supply I have been using, turned it on and away it went.Checked the 40106 and all the wave forms are distorted,no clean square waves anymore bumps in the tops and in the trace before or after the main pulse.Disconnected wall wart and reconnected battery,turn it on and away it went no problem,on and off again several times keeps on working.The 40106 wave forms are still distorted, This 40106 has got to be failing,Any body got any ideas. I ordered a few trigger chips just to have,I dont trust it anymore.

[bernte_one]

hello

thanks all for answer

red colored pbc has correct marking i checked it
same good quality like everytime

but bad components (my own components laying around here)
not from silverdog

i supposed that the a different pinout version from 79l05 and 78l05 but it is not so checked it with datasheet and alright so

changed icl7660 to 7660s same problem when i take the 7660 off pcb the 78l05 get hot very quick

i think problem is at 78l05 or the diode 1n4148 nearby
will check all tomorrow with fast measuring


feel not good today
big climate change here from 30degree celsius to 12 degree
makes me tired

regards bernd

[Brian Deese]

hello

i replaced icl7660 and measure 78l05 and 79l05
78l05 gnd and out 6V
79l05 gnd and out-0,9 V

is this normal 78l05 get hot very quick when i replace the icl7660

if anyone can say what i should measure in this situation i would be a help

regards

7660 pin 8 is Batt voltage 12v max for 7660,pin7 is clock pin and has a capacitor charging wave form on it If I remember correctly,pin 6 not used,pin 5 is the invertered Batt voltage -12v,pin 4 has a negative going square wave,pin 3 is ground,pin2 has a positive going square wave on it,pin 1 not used. I would take the regulators out of circuit before I went any further,the 7660 is the most expensive chip on the board.

[silverdog]

hello

i replaced icl7660 and measure 78l05 and 79l05
78l05 gnd and out 6V
79l05 gnd and out-0,9 V

is this normal 78l05 get hot very quick when i replace the icl7660

if anyone can say what i should measure in this situation i would be a help

regards

Sounds like something wrong with 7660
I'd give the bottom of the pcb a good clean
Measure 7660 pins 5,8
78l05 input voltage ?
The Red ApBerg pcb I supply is correct for silkscreen for all the ones I have made

[6666]

On all my barra boards the 7660 is dead cold and I measure around + and - 5 volts

[bernte_one]

hello

i replaced icl7660 and measure 78l05 and 79l05
78l05 gnd and out 6V
79l05 gnd and out-0,9 V

is this normal 78l05 get hot very quick when i replace the icl7660

if anyone can say what i should measure in this situation i would be a help

regards

[bernte_one]

hello

maybe there was wrong printing on pcb (red one)
and i have to invert 79l05 and 78l05?

i dont know anymore will check it this evening
or are there different types of 79l05 and 78l05?

regards

[bernte_one]

icl 7660 problem

hello

i have a problem with the icl 7660
after switch power on it becomes hot very fast
no idea where the problem starts
coil hooked up and no sound at headphone
have build it like the two other pcb
but this is first time i have problem at icl 7660

maybe it is a broken icl 7660

any idea?


rgards bernd

[Brian Deese]

Here is some pics of my madness.

[Brian Deese]

Ok Barracuda is running now. Question about coils and sheilds.

After working on my surf pi for a couple days I decided to pick the barracuda up again.Idont know what I had done but the mosfet was dead,and I smoked the 2n2222 poking around with a jumper.Now when I figured out what was going on i stoped and went to town for a pin vise to clear out the holes in my board as I have been having a terrible time replacing components.I didnt find the pin vise but I found circuit board reamer and assorted other tools at harbour freight tools.Man this thing has saved my life,you may not use one I dont know but for me that reamer is the cats pajamas.Ok so the only mosfet I had was the irf9520 which I want to use anyway since it has around 170pf Coss instead of 370pf like the 9640.However it is a 100v device,which may or may not be a problem.I have had much better results with this mosfet in my testing on the surf and barracuda so far.I replaced the mosfet and the 2n2222,and away she went,semi smooth threshold.Checked the preamp output and no ring with a 550ohm resistor,so I set the offset,and the delay.All the while I am monitoring temperature of mosfet.This is where it gets interesting or maybe confusing,the preamp is in saturation for about 20us so I can only sample as soon as 25us or so,I suspect this is due to the coil is 444uh 11" and 1.6ohms,24awg teflon,no faraday sheild yet.4 ft of rg62, with the barra's tx pulse width I guess it is what it is.So with these settings I get ok detection distances so I decide to check the damping and see if I can loosen the coil up some.I goes all the way to 1.5k with no ringing,I dont understand it.Much better sens now,still not where I want to be yet but getting there.Do I need a sheild if I sample at 25us? My threshold comes up near the end of my pot travel,is that normal? What is up with this coil damping at 1.5k? What is the best coil for your barra?I see alot of 25-30cm claims on here and I am not there yet.I gona post some pics for you guys.

[bernte_one]

hello

what should this lcd display?

detection depth or still "target found"

the only what i have palnned ws to connect a lm3914 vu meter to show signal strenght via led insted of usinf headphone ore one singel led

regards

[satdaveuk]

I made a nice circuit board for the barra months ago maybe shall populate it soon.
Has anybody here done a lcd setup for this project yet?
Just a thought

Regards

[Brian Deese]

I think 28AWG may be too thin, your resistance is high
something like 24AWG may be better

In bbsailors pdf "Making a fast pulse induction mono coil" He uses 30 awg wire and ends up with 5.4 ohms resistance.The resistance should limit the current in the mosfet to 3amps,which should not make it get hot. Nice kits,I put the surf pi together also but I want to get barra perfect before I move on.

[silverdog]

I think 28AWG may be too thin, your resistance is high
something like 24AWG may be better