Seem's it would be IC32 or IC33 (or both), they toggle the lowest
address line, so when enabled all the addresses would be even or when
disbaled all addresses would be odd....however, I'd assume if they
were busted, it wouldn't just be RS/CB....it would affect all sounds
that are shared (BD1 & BD2, SD1 & SD2)....is it the same problem will
all the sounds or just the Rimshot & cowbell.

ryan

--- In tr-707@yahoogroups.com , "philo_707" <philo_707@...> wrote:
>
>
> Do you know which IC is responsible for routing between interleaved
> sounds I have a dead 707 that first stopped routing, so that it
> worked great except that there was no rimshot, both rim/cow played
> cow and so on, although the sound sets sequenced normally.
>
>
>
>
> --- In tr-707@yahoogroups.com , "plutoniq9" <Plutonique9@> wrote:
> >
> > Eprom's, like all parallel memory, addresses it's memory in binary
> > format. Think of the address lines as being binary inputs....for
> every
> > address line you add, like binary, doubles the amount of locations
> > (numbers) it can access. Inside the memory, the address pins are
> > decoded to select different areas of the memory.
> >
> > 1 address lines = 1bit :: 2 values (memory locations)
> > 2 address lines = 2bit :: 4 values (memory locations)
> > 3 address lines = 3bit :: 8 values (memory locations)
> > 4 address lines = 4bit :: 16 values (memory locations)
> > 5 address lines = 5bit :: 32 values (memory locations)
> > 6 address lines = 6bit :: 64 values (memory locations)
> > 7 address lines = 7bit :: 128 values (memory locations)
> > 8 address lines = 8bit :: 256 values (memory locations)
> >
> > and so forth.....
> >
> > So, imagine you have a 32k X 8-bit eprom, that would require 15
> > address-lines (32,768 memory locations)...that is what the size of
> > each eprom is in the 707/727. If you wanted to double your memory
> > (sample banks) would only require an addition address line (each
> > address line doubles memory that can be accessed)....seeing as
> address
> > lines are just binary inputs, you can see how it would be easy to
> add
> > a single switch to toggle on/off (+5v, 0v) that extra address line
> to
> > switch between your (now) 2 banks of memory.
> >
> > That's what circuit bending is all about, they cross (short)
> address
> > lines which causes errors in the memory location access, which
> cause
> > the glitch sound....
> >
> > So, the way the 707 samples are interleaved in memory are just
> > organized in a linear way (just like a mono recording), one sound
> > after another. But what has stopped all the eprom hackers from
> going
> > ahead with new samples for these machines (unlike drumulator or dmx
> > for example) is that the sounds (like BD1 & BD2) are intereleaved,
> and
> > they've been too lazy or unimaginative to proceed, saying "it's
> > impossible" and hopeless shite like that :) Intereleaved sounds,
> think
> > of 'em like this;
> >
> > BD1 sample1 -> BD2 sample1 -> BD1 sample2 -> BD2 sample2 -> etc.
> >
> > after all of the BD samples are over the next sample set follows
> > (interleaved)
> >
> > SD1 sample1 -> SD2 sample1 -> SD1 sample2 -> SD2 sample2 -> etc.
> >
> > Pretty simple heh :)
> >
> > I taught myself some C++ basics through online tutorials, though
> > because i do audio DSP, i use the Synthedit SDK to develop stuff,
> > which is a great platform. Check out these sites;
> >
> > http://www.cee.hw.ac.uk/~pjbk/pathways/cpp1/cpp1.html
> >
> > http://www.cprogramming.com/
> >
> > http://www.cplusplus.com/doc/tutorial/
> >
> > That should get ya started
> >
> > Seeya
> >
> > Ryan
> >
> >
> > --- In tr-707@yahoogroups.com , "acousmatique" <acousmatique@>
> wrote:
> > >
> > > --- In tr-707@yahoogroups.com , "plutoniq9" <Plutonique9@> wrote:
> > > >
> > > > According to the service manual, they are interleaved quite
> > > > simply.....sounds that are shared (ie. BD1 & BD2) have occupy
> the same
> > > > adreesses, except one has even adresses & one has odd....you'd
> have to
> > > > write a small application that would organize new samples in
> this
> > > > way....but it's a simple routine & probably within my C++
> scope.
> > >
> > > Arg... This is where my understanding of digital drum machines
> has
> > fallen apart! I have
> > > read quite a few tutorials on EPROM addressing, and I still
> doubt if
> > I get it. Maybe I'm
> > > thick! Also I have no C or C++ experience. Any advice on
> how/where I
> > can learn about
> > > coding for low-level stuff like this Or even what key words I
> might
> > want to search for
> > > Happy it's within *your* scope, anyway! >;]P
> > >
> > > CJ
> > >
> >
>