Falcon MD20

[WM6]

some small improvements to circuit help stability

Nice, thanks.
Do we really need 12V supply? Is 9V not enough?

[dom44]

some small improvements to circuit help stability

[homefire]

Looking GooD Sir.

[dom44]

Try it now forgot to hit publish button

[dom44]

https://www.youtube.com/watch?v=Ccldy4cSLkk&feature=youtu.be

[homefire]

VIDEO UNAVAILABLE Emmmm

[homefire]

Sounds like a plan.

[dom44]

This is where i am now quick clip using my ring as the copper ring the metal piece is a 2.5 mm component wire distance is about 5mm from tip of rod, you cant see it but the metal piece dances to the magnetic field when you get close.

[dom44]

The diodes are garden verity 1N4148 they are there to steer a positive voltage to the base of T1. the output speaker drive is from tesoro designs the way it works is T1 changes the frequency when positive voltage applied and T2 controls the volume when positive is applied, the back of the diode is facing the base of T2 so will not conduct but the moment you apply a positive voltage to the base the square wave from the oscillator modulates the base and the volume is proportional to the voltage as well as the frequency,
I have the circuit working but am not happy with the frequency swing not enough voltage swing from the detector.

[homefire]

Dang Tim. Sorry to be hearing that. You can do fine without a pancreas. Can't they remove it or has it moved around ? It's Never over until the Fat lady sings, Right ?

Dom, Novel Idea on the VCO. What Diode was you thinking there. I see a zener being used in other Nand Gate VCO's. Don't understand how they work.

[dom44]

This is the VCO looking for A,B and C Values A is 1meg and works fine image4 is wrong BC327 is upside down cant remove it.

[dom44]

sorry to hear about your cancer Tim have lost a lot of family and friends to it to the point a did a lot of research on natural therapy's and there is so much we are not being told i know this because i have quite few proven cures that don't involve poisoning your body or radiating it or cutting it up, look up Hoxsey formula or essiac for a start,
I have almost finished the VCO section works great but not getting enough tonal change for my liking I have to play with some part values still.

[Tim]

Sorry y'all for not replying- been a bit crook. Great progress dom !! I ended up buying an original off fleabay- too many un-finished projects. They are a great little piece of kit. Glad you could explain to homefire about the 555.
I hope to return and contribute here more in the future, but I have just started my second month of Chemotherapy for inoperable stage IV pancreatic cancer, so have been a bit doughy. It's been knocking the crap out out me, but I hope for better health and less side effects in the future.
All the best to you all at this wonderful site. : )

[dom44]

Resistor missing

I left out a 3k9 resistor emitter of T2 this is fixed now and i have just built the second one on the PC board and I know it works well. with just the LED and no sound when adjusted you can see the LED flicker at over 100mm with the tip of a small screwdriver near the search coil.

[homefire]

Good Stuff. Thank You.