[sdiy] CMOS clock problem

[harrybissell at wowway.com]

Do you have a schematic ?

I'm assuming its the traditional two-gate oscillator with
one capacitor and two resistors.  One resistor and the cap
sets the frequency, the other resistor is in series with the
gate input to stop the input diodes from being too much of a pain
in the @ss.  The resistor to the input should be about 10x the size
of the frequency determining resistor.

It could be that loading stops it from starting... is the output
buffered ???

H^) harry



On Mon, 21 Apr 2008 16:44:43 -0400, mark verbos wrote
> Hi,
> 
> I have a high frequency clock made out of a couple 4001 gates in my  
> quantizer module. It doesn't like to start clocking when I turn it  
> on. Then I touch the pins with the scope probe and it starts going. 
> I  tried adding a 2.2M resistor to ground on the pin where the cap 
>  connects and I got it to start if I plug the connector in while the 
>  cabinet is powered up, but if I power cycle it while plugged in 
> it's  not oscillating. Is this something to do with the order that 
> the  power rails are coming up? It's only using +15 and GND, so I 
> don't  see how it could.
> 
> Any ideas? I'm lost.
> 
> Mark
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Harry Bissell & Nora Abdullah 4eva