I recently got my Roland TR-606 back from exfade after some serious modifications.
Each sound has a range of mods to it , whilst still being the basic Roland TR-606.
I’m pretty happy with the mods and the kick drum is a beast with the long decay.
The 606 itself is a bad way though so it looks like it might need a new sound select and volume pot or at least a good clean.
You can hear all the different drum sounds and their various permutations here, feel free to download and slice, for your own projects. These are recorded out of the main out rather than the individual outs at the back so there is a bit of cross noise.