Its good to be on board. This is more for the group
then for you, Ryan. Although Im not very familiar with
TR-707 or 727 I am familiar with the other machines
with similar schemes for PCM Audio or Voice storage on
Masked ROMs. The memory upgrade Im working on is for
the HR-16 and the Sk-1. I know the schemes are
different but they will share some similarites.

Resently Ive heard about an effort towards cracking
the scheme used by Roland on the TR's so I thought I
would jump on board and see where I could help. I do
plan on getting one of the drum machine here in the
near future but they've been going for a bit more then
I can shell out at the moment.

--- plutoniq9 < Plutonique9@... > wrote:

> Hi Jesse,
>
> Things are startin' to look a lot better if we have
> you onboard :)
>
> Here's the situation, compared to a standard 27c256,
> the Roland mask
> ROMS differ in this regard (i compared schematics).
>
> -(12) of the (15) address lines do not follow the
> jadec standard
> arrangment. However, every address pin except *(1)
> correspond to
> address pins on a 27c256.
>
> -*Roland ROM utilises Pin 26 as a CS (chip select) &
> Pin 20 as an
> address-line. These Pins would have to be reversed
> if replacing stock
> ROM's with 27c256's and also when reading the
> original mask ROM's.
>
> -Roland OE (aka output enable & chip enable) is
> active "HIGH", while
> standard 27c256's are active "LOW".
>
> -One of the (2) ROM's used for the bulk of the
> sounds needs an active
> "HIGH" for CS (chip select), while the other needs
> active "LOW".
> 27c256's are active "LOW" for CS.
>
> Everything else is the same, Data pins D0->D7 line
> up, VSS & VDD same
> and (3) of the (15) address pin's line up to the the
> jadec standard. I
> believe we could design a converter board with not
> much space and
> minimal external parts, some resitors and PNP
> transistors to invert
> the CS/CE states. I already started on listing what
> pins of the Roland
> ROM's correspond to what addresses.
>
> Seeya
>
> Ryan
>
> P.S I need manage once to get the ROM to read, but
> the data wasn't
> useable and I thought it was an error, this was
> before i thought their
> was a compatability issue.
>
> --- In tr-707@yahoogroups.com , Jesse Smith
> <stoi2m1@...> wrote:
> >
> > Im not giving up, I have at least three other
> machines
> > that implement the same type of method to protect
> > their samples as well. And I may possibly have
> more.
> >
> > I do have experience using CAD software for
> designing
> > PCB's I use a program called eagle soft which can
> > output the file typ some manufactuers need but I
> think
> > another one is PCB123 (or something like that).
> >
> > I like your ideas they come from a new angle then
> most
> > approches i have taken in the past. Dont be
> > discouraged Ive been looking and messing with this
> for
> > at least a year.
> >
> > Ill work on some schematics for ways to rearrange
> the
> > address pins and do some talking to see what may
> be
> > the easiest way to switch them.
> >
> > All of this will not help you with your situation,
> if
> > the address and data pins are all rearranged but
> the
> > address pins are sill in what is suppossed to be a
> > Jadec posistion and the data pins are also in a
> Jadec
> > posistion then you should be able to read from it,
> > even if the data is jumbled. So the issued lies
> with
> > is the chip powered and is one of the enable pins
> > active high instead of low, and is your programmer
> > reading properly.
> >
> > We now your programmer is ok, for you have read
> other
> > chips in with it. So it seems like a chip enable
> > problem again, but the pins could be jumblem much
> more
> > then we think, so hunting and poking will probably
> be
> > the best method and build a chart of all possible
> pin
> > variations.
> >
> > Jesse
> >
> > --- plutoniq9 <Plutonique9@...> wrote:
> >
> > > Ok,
> > >
> > > I desoldered & pulled my TR-727 sound ROMS and
> > > thought I'd get my
> > > hands dirty with ripping the sound data from 'em
> to
> > > see how they are
> > > all organized. After mnay hours of trying this
> and
> > > that to get 'em to
> > > read, I went back and looked at the schematics.
> > >
> > > 9.9 times out of 10, all eproms of same # of
> pins
> > > have an indentical
> > > pin layout, this even holds true for parrallel
> SRAM.
> > > It's called the
> > > Jadec standard and was created for compatibility
> &
> > > ease of mind for
> > > developers...much like many standards.
> > >
> > > But if your a paranoid company like Roland, and
> > > think people are gonna
> > > poke their noses in where they don't belong
> > > (hardware wise), you'd
> > > step away from this standard, re-arrange all
> your
> > > pins (or most of
> > > em)....and thus make them incompatible with
> eprom
> > > readers and make new
> > > custom chips more than just blowing a new ROM
> and
> > > replacing the other
> > > chips. That's what route they took with the
> TR-707,
> > > TR-727, TR-909 &
> > > probably the 505 & 626.
> > >
> > > They've basically implemented a pretty good copy
> > > protection system.
> > > Basically, in order to rip & burn new ROM's for
> the
> > > 707/727, one would
> > > have to build a custom PCB that re-routed (12)
> > > address-lines & a CS
> > > (chip select) line. In addition, both CE
> > > (chip-enable) pin, and a CS
> > > of one of the two ROMS, would have to be
> converted
> > > from rolands
> > > "active = high" to standard Jadec "active =
> > > low".....
> > >
> > > Not impossible, but we'd need to have some PCB
> > > boards made up to even
> > > take the first step. But if we were to go this
> far,
> > > you may as well
> > > design the board to accomidate a 32-pin eprom
> for an
> > > additional
> > > 16-banks of sounds. I see (2) small pcb boards,
> with
> > > a 32-pin DIP
> > > socket and 28-pins for soldering into the
> 707/727
> > > PCB + a couple PNP
> > > transistors & resistors for inverting the CE &
> CS
> > > states.
> > >
> > > We'd probably need 10 people willing to pitch in
> to
> > > have the boards
> > > made up (because most PCB board producers have
> > > minimums), and someone
> > > who has experience using PCB design software,
> most
> > > PCB producers
> > > actually have their own software they require
> people
> > > to design on.
> > >
> > > Wow! Is it worth it Are people completley
> bummed
> > > out and are now
>

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