Hi Peter,
Your P6 problem is really starting to bug me! Could you take a
voltage measurement from IC17 between pins 5, 6, and 7 and ground? It
will be interesting to see what is going into the mux.
Cheers,
Andy
--- In PolySix@yahoogroups.com, "Andrew Jury" <andy@...> wrote:
>
> Peter,
>
> The logic probe measures whether logic states in TTL or CMOS
> circuitry are a binary 1 or 0. Remember we talked about how the
> binary pattern on lines A, B, C, INH set which outputs on IC31 are
> selected? This tool would tell us how they are set and whether they
> were switching on a the right time.
>
> However, from the description how the six LEDs are lighting up
(yes,
> one after the other in POLY mode - I am an idiot!) it sounds like
> IC31 is working correctly and keyboard assigner is sending the
right
> binary pattern to the switch.
>
> I expect the input on pin 3 is the problem. What I will do is take
> some reading from my working Polysix and let you know how the
> circuitry should function. I'll post this after the weekend, if you
> can wait.
>
> Also, I'll take you are playing with the settings in manual mode
and
> not from the patch banks? When the SRAM (memory) failed on my P6
the
> patch banks just contained random bit patterns which produced sound
> which could be very much be described as 'out of tune'! Just a
> thought...
>
> Cheers,
> Andy
>
>
>
>
> --- In PolySix@yahoogroups.com, "hjulskov" <hjulskov@> wrote:
> >
> > Thanks Andy,
> >
> > The LEDS (D10) does light in order in polymode (which I think was
> what
> > you meant?) -in unison they all light simultaniously.
> > In Polymode all voices sounds equally (bad).
> >
> >
> > I'm not sure about your last question (Can you lay your hands on a
> > logic probe at all?)?
> >
> >
> > Cheers,
> > Peter
> >
> >
> > --- In PolySix@yahoogroups.com, "Andrew Jury" <andy@> wrote:
> > >
> > > Hi Peter,
> > >
> > > I am afraid we can't make that assumption until the logic that
> controls
> > > IC31 has been tested. This device is basically a switch. You
> apply a
> > > binary pattern to lines A, B, C and INH and this determines
which
> one
> > > of the outputs is connected to the input. The input is marked X
> the
> > > outputs marked X0, X1, X2, etc. It is the outputs which we just
> tested
> > > and which don't seem to move. Tell me, do the voice LEDs (D10)
> come on
> > > in order in Unison mode? Everytime you press a key an alternate
> voice
> > > LED should light up. I suspect not?
> > >
> > > Can you lay your hands on a logic probe at all?
> > >
> > > Cheers,
> > > Andy
> > >
> >
>