Hi folks,
I'm pretty new to circuit-bending, although I've been building,
repairing and modifying electronic equipment for a while now. I was
pretty interested to read http://burnkit2600.com/gear/ p=24 - a page
about the TR-626, because I've got one of these.

My new EPROM programmer arrived on Saturday, so I set about making up
new Simmons and Drumtraks ROMs - all good and well but what about the 626

Well, it turns out that the ROM is a plain ordinary JEDEC
mask-programmed 2Mbit ROM. The samples are 8-bit unsigned linear, and
the sample playback is via a simple resistor ladder. Easy, eh No.
The address lines are mixed up in a complicated manner, so it's not
just a case of going through the ROM and picking out the bits you
want. However, with a bit of thought I was able to hack together a
rather crufty bit of C which will straighten out the ROM address mapping.

I've put a .zip file with a raw dump of the ROM, and the decoded
version: http://static.nekosynth.co.uk/tr626.zip

Now if you can decode the ROM, you can encode other samples to fit
into the ROM, right Well yes, of course! So, here it is,
href=" http://static.nekosynth.co.uk/tr628.zip - a
ROM set with some of the samples replaced with TR808 samples.

You'll need a 2Mbit EPROM or FLASH chip to blow the file "tr628.bin"
into, although a 1Mbit would do at a pinch (I'm using a 1Mbit just now).

Have fun, and be careful!

Gordon