[sdiy] sucess stories :)

[patchell]

Nils Pipenbrinck wrote:

> Hi folks,
>
> I spent the weekend building my asm-1 vco.. Of cause I didn't oscillated at
> first (but turned one of the opamps into a cloud of smoke). Anyways.. after
> reading the diy-list archive archive I found everything to fix it.
>
> Just in case someone is going to build the asm-1 vco and is lurking on the
> list here are a couple of hints:
>
> The LM311 voltage comparator has a pin called "ground". (that's pin 1). Even
> if it's called ground it should be connected to -15V to work properly. It's
> also a good idea to connect pin 5 and 6 (balance and strobe).
>
> The 18pF cap behind the LM311 is somewhat critical. I think it depends on
> the Fet used, but for me the fet didn't discharged the integrator-cap. I
> replaced the tiny 18pF with a 47pF. That fixed the problem.
>
> Also, it's a rather good idea not to solder the expensive MAT-02 into the
> board when you test it. Next time I'll first use two 2N3904 and replace them
> when the vco is working. (I learned that the hard way).

    Sometimes learning stuff the hard way is the best way....I just wish that
sometimes it wasn't quite so expensive!

>
>
> Bye,
>     Nils
>     (now a proud owner of his first selfmade vco)

--
 -Jim
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* Visit:http://www.silcom.com/~patchell/
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