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
losing interest, if not who could help on this project. It would suck
to talk about it this much and then to give up.

Ryan