Finished building an SSG last night and am having similar issues. Keep popping LM3900s. They go fast and extremely hot! Checked traces (I'll check again) but haven't troubleshooted extensively yet. btw, I used J201 (not J201A) and 50v 10uf Electrolytic (not 25v) and somewhat concerned about the 100pf cap (looks like mine says 101. Should be correct). I'll get back in touch.
Thanks, Sean
Thanks, Sean
--- In cgs_synth@yahoogroups.com, sasami@... wrote:
>
> Okay, those voltages were more or less what I got.
> Now take a 1k resistor and connect one end to -15. Connect the other end of
> the 1k resistor to each input pin in turn, and read the voltages. If all is
> well, they will read around -14.5 to -15 volts. If any read much higher than
> that, that is probably where the problem is.
>
>
> Below are what I got on those pins with chips IN.
>
> >1) -14.3
> >2) -14.3
> >3) -14.3
> >4) -14.5
> >5) -14.8 (Smooth) +14.8 (Stepped) (this will depend on what the module is
> doing!)
> >6) -14.5
> >7) -15
> >8) -14.9
> >9) +14.2
> >10) 0, -0.2 (Stepped)
> >11) -14.5
> >12) -14.5
> >13) -14.5
> >14) +15
>
> Other than that, it would be high-resolution pic time.
>
> Ken
> _______________________________________________________________________
> Ken Stone sasami@... otherunicorn@...
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>