A few weeks ago Dejan and I began our work on Hammond XB-2 again. The current problem can be heard here:
We tracked the problem back to the static RAMs, which was also mentioned as a solution in one of the comments on this similar youtube video.
We opened the keyboard and took out the main board. As you can see in the picture below, somebody already played (changed) the MUSE RAM chips (the size is different, thus the chips are hanging by the wires – top right corner).
Suprisingly, this thing worked in its own distorted way …
We unsoldered the old chips and cleaned the board …
We also made sure we have the right DIL (dual in-line) sockets and put those on first.
Dejan obtained the replacement chips from old computer boards. These are not identical to the originals (the new ones must be newer since the old ones had 70ms latency according to the manual) but should do the job.
However, the problem remained. Next step: change the V61C16 chips. Unfortunately we don’t have those and need to find them (or their alternatives) first. If anyone has any information on where to get them, please let me know!