OK, so my mistake was to call the common feedback rail pin "ground". This is what I was connecting to the other pins to try to generate a MIDI note, as described in the manual, not to an arbitrary ground.

Sorry for my initial inaccurate explanation.

Sean

--- In Doepfer_a100@yahoogroups.com , <yahoo@...> wrote:
>
> Sean,
>
> you find my comments written inline.
>
> Dieter Doepfer
>
>
> > I'm aware of the triggering setup for the CTM64 and how it works
> > with shorting a pin to ground to get a trigger.
>
> That's not the way how the CTM64 works ! Please refer to the CTM64
> information:
> " Pay attention that only free contacts can be used. This means that the
> contacts are not allowed to be connected with another electronics or
> connected with a fixed voltage (e.g. GND)."
>
> > I was using it about 8 years ago with a calculator keypad attached to my
> bass
> > guitar to trigger MIDI events in Logic.
>
> I cannot imagine that this was working ever ! The 64 connectors of the CTM64
> are outputs (!) that are normally in the high state and change to the low
> state for 1/64 of the scanning time. If you connect one of the CMT64 pins to
> GND nothing will happen. You have to use the common feedback rail
> (attention: this is not GND but a line that carries the scanning feedbacl
> signal) to make the CMT64 working.
>
> For details please refer to the CTM64 user's manual
>
> > I haven't powered it up for ages and it doesn't want to play nicely
> anymore.
> > I've tried shorting the ground pin to any of the individual
> > contact pins but it doesn't output a trigger.
>
> That's what I would expect.
>
> > All the jumpers are in place and haven't been moved since the
> > original setup.
> >
> > I have no experience with PIC chips so am not sure how
> > serious/terminal a problem this is.
> >
> > Anybody experience anything similar
> >
> > Sean
> >
> > --- In Doepfer_a100@yahoogroups.com , Florian Anwander
> > <fanwander@> wrote:
> > >
> > > Hi Sean
> > >
> > > > Mine's not sending any MIDI output when triggered, and the
> > triggering doesn't dim the LED.
> > >
> > > Just to make clear, that I do not misunderstand you: You know that the
> > > CTM64 does NOT convert triggers to MIDI It is intended for old organ
> > > keyboards (and similar) which have one common wire, and 64 contacts,
> > > which can be switched to this wire.
> > >
> > > IT DOES NOT WORK WITH TRIGGER INPUTS!
> > >
> > > Florian
> > >
> >
> >
> >
> >
> > ------------------------------------
> >
> > Yahoo! Groups Links
> >
> >
> >
>