[sdiy] sucess stories :)

[Nils Pipenbrinck]

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).

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