[sdiy] My 4069 attempt not working

[René Schmitz]

Nicolai Czempin wrote:
> René Schmitz wrote:
> 
>>
>> 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. (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.)
> 
> 
> Here are the (estimated off the oscope, I can give more precise values 
> off the DMM if you need them) readings on the different pins. All are DC 
> voltages, with no oscillation noticeable:
> 14: 9V
> 13: 0V
> 12: 9V
> 11: 6V
> 10: 0V
> 9: 0V
> 8: 0V (Shouldn't this be inverted somehow??)
> 7: 0V

It could mean that one of the gates is fried. Or maybe that the brigde 
from  pin 9 to 10 is flakey. It seems the schmitt output pin 8 is 
sinking to GND, thus dividing the 9V from pin 12 by 3/2 giving roughly 
6V. Try rebuilding the schmitt trigger with the gates of the lower half.

Oh, and by the way, you should ground unused gate inputs, they shouldn't 
be left floating.

Cheers,
  René

-- 
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159