> Once I know how the drum sounds are layed out in memory, I can put some
> new ones! CJ

Now y'all have done it... I broke down and ordered a basic EPROM
programmer to jam this with. In theory, 62256 SRAM should work.

Yes, the sound locations are in the service notes, on page 7 of the scans I
have on hand.

We should be psyched that Colin Fraser has saved us from reinventing a
tremendous amount of wheel. On his site he describes in detail how he made
clones of the 909 cymbals, which just happen to be done on the same chips
in a nearly identical circuit. Some mods are neccesary in order to use garden-
variety 27256 EPROMS, and those are described here.

< http://www.colinfraser.com/tr909/909cyms.htm >

Colin had more leeway, as he didn't need to fit this on a real 909 board. It will
require some work to apply this towards dropping an EPROM into a 707 and
having it work.
Laterz