TR-909 Dual Firmware Mod

This modification replaces the firmware EPROM on the sequencer board and provides a micro switch in the battery compartment to switch between two different firmware versions (V1 and V4 are provided).

It also replaces the stock AA battery holder with a snap in kind that will not rattle around.

Finally, there is a trimmer to dial in a perfect amount of snare “snappy” on the TR-909 clones like the RE-909.

Comes fully assembled/soldered with pre-flashed EPROM, ready to install.