SBG-PID

[6666]

Here is the story
On the SCS schematic, he shows capacitors C11 and C12, they are across + battery and the new - voltage
with out C12 220uF the power supply oscillates, this oscillation wave form now appears on the + and - 4 volt voltage rails, and destroys the TX 555 pulse out.

On the Ivconic schematic he has drawn these two caps c11-c12 as C23 and C24, but seems to have omitted them from the PCB layout, or at least I cannot find where they go.
To fix this, I have soldered a 220uF cap across U5a +and - rail and the oscillation has stopped the rails are now clean DC and the pulse from the TX 555 looks ok
U5a is a rail splitter and produces + and - 4 volts

If you make this circuit make sure that the capacitor is in the circuit, and at least 220uF


( As a side note I modelled this in spice, (crash coarse cannot believe it worked ) how the heck does spice know the power supply oscillates with out the 220uF cap across it ? )

[dbanner]

Good on you for catching that. I hope one day to return to work on this circuit.

[bernte_one]

have several pcbs here, i run out of time and interest
so i offer pcbs europe wide

[6666]

Anybody made it yet?
Any video?
I am too busy in this period, unfortunately i can't have time to pay on this.
But i would really like to see if somebody make success with this detector.

Ivconic, when you laid out the PCB which schematic did you use ?, thanks.

[ivconic]

Ivconic, when you laid out the PCB which schematic did you use ?, thanks.

[nickel_n]

Hey 6666
did you manage to get it running?

[6666]

Hey 6666
did you manage to get it running?

Hi Not yet I discovered a problem with the PCB just trying to sort out whats going on.

[nickel_n]

Thank's 6666

[6666]

Hello Ivconic, I have discovered late last night that your PCB layout does not match your redrawn schematic pin numbers.
I guess I missed a post about it.
But when I buzzed the pcb this is what I got
u3a pins 567
u3b pins 123
u4a pins 567
u4b pins 123
u5b pins 567 correct labels
I think I got this correct or I have embarrassed myself

[ivconic]

Hello Ivconic, I have discovered late last night that your PCB layout does not match your redrawn schematic pin numbers.
I guess I missed a post about it.
But when I buzzed the pcb this is what I got
u3a pins 567
u3b pins 123
u4a pins 567
u4b pins 123
u5b pins 567 correct labels
I think I got this correct or I have embarrassed myself

Yes is true.
Why is that?
First i draw schematic. And is not important whether you will use first or second opamp in dual packaged opamp.
But later when i try do draw pcb according that schematic; sometimes is more easy and more convenient to switch opamps from dual (or quad) and use second one instead first on specific place on pcb.
As long as inverting, non-inverting and output pins are on the same place where supposed to be.
It is the same if you'll use "567" or "321". Opamps inside are the same.

[6666]

sometimes is more easy and more convenient to switch opamps

No worries , I thought that was the reason,
just thought I would mention it for other people making the project, I'm still waiting some parts.

[zakari]

hi all
i made this detector but not working
vt9(bc337) has been hot and sound is continuse
i made the original sasho's pcb
best regard
zakari

[zakari]

hi sasho
if you are here yet please help me
i made according this schematic

[zakari]

hi all
the pcb's

[ZOUjiarui]