Thanks Dave, this ones been making me crazy !
So, i took my son to his soccer game and got back and fired it up and now both sections are working after popping another 3900 in the stepped section.So either i have a whole bunch of bad luck w/ the 3 different batches of 3900's i have, or as i really suspect i have some funky stuff electrically going on.
So for now i guess i'll just rock this thing out and keep my fingers crossed.
Thanks gain Ken for being so generous with your time i really appreciate it !
So, i took my son to his soccer game and got back and fired it up and now both sections are working after popping another 3900 in the stepped section.So either i have a whole bunch of bad luck w/ the 3 different batches of 3900's i have, or as i really suspect i have some funky stuff electrically going on.
So for now i guess i'll just rock this thing out and keep my fingers crossed.
Thanks gain Ken for being so generous with your time i really appreciate it !
--- In cgs_synth@yahoogroups.com, Dave Kendall <davekendall@...> wrote:
>
>
> On 13 Apr 2013, at 18:24, adematteo wrote:
> > So, i'm assuming there's an intermittent short or fragile trace that
> > i'm not catching ?
>
> FWIW, I've been caught by them before - once a *very* tiny sliver of
> solder bridging things it shouldn't, and another time an almost
> invisible etching fault. The solder sliver had fallen from a solder
> sucker when tweaking/subbing components, and had lodged somewhere
> awkward.
> Back when my eyes were pretty good, I still didn't spot either until a
> magnifying glass was used.
>
> Good luck - hope you find it.
>
> cheers,
> Dave
>
>
> >
> > --- 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@
> > > Modular Synth PCBs for sale <http://www.cgs.synth.net/>
> > > Australian Miniature Horses & Ponies
> > <http://www.blaze.net.au/~sasami/>
> > >
> >
> >
> >
>