[sdiy] My 4069 attempt not working

[Nicolai Czempin]

René Schmitz wrote:

> Hi Nicolai,
>
> Nicolai Czempin wrote:
>
>> Can someone help please? "Just" a walkthrough as to what I should see 
>> on the scope at certain key points would be very helpful.
>
>
> It would be easier for us to tell whats wrong, if you told us what you 
> observe at the integrator output, the first and second gate of the 
> schmitt trigger.


Sure, any which way I can help you help me will do.
I have actually

> (There is supposed to be a sawtooth sitting arround Vcc/2 at the 
> integrator output, and discharging pulses (going high for about 1us) 
> at the schmitt trigger output, and the inverted version of those 
> pulses at the junction of the two schmitt trigger gates. But thats not 
> going to help you, since the pulses wont be there, if there is no saw, 
> and vice versa.)
>
> Does the 4069 have V+ connected to pin 14? Do you read 0 ohms between 
> pin 7 and  GND?

I have connected 14 to V+ and I have connected pin 7 to GND. How can I 
not be connecting it but merely reading it?

>
> You can confirm that the expo current source (err sink, whatever)
> is working by disconnecting it from the integrator, and running the 
> collector of T2 to V+ through a DVM (current reading) and a 1k in 
> series. (The latter to protect the DVM.)
> Its ok, if reading somewhere between a couple uA to some mA.

I'll try that at another stage (if necessary), for now I'm looking at 
the oscillator itself (having replaced the sink with a 100k pot and 4.7k 
resistor as suggested).

For what it's worth, I have posted the best of my bad photos at my 
weblog. It's not really possible to see anything like resistor values, 
but it should give a rough idea.
http://www.czempin.de/nicolai/blog/archives/000273.php