The full-length riser was cleaned inside with a pipe-cleaner and, after deciding to discard the clarinet register relay which had been mounted at the back, I worked on designing and implementing a membrane register action within the riser itself. This involved tracing the positions of the internal channels, routing into the side panel and to create openings.
The centres of these openings were then blocked, and the edges rounded-off. and separating walls created. These were fitted with pneumatic sheepskin skiver to form the membrane. This feature was covered with a sealed "lid", and the riser re-mounted onto the chest in the organ.
Now was the time to mount the divider frame, which stands between the trombones and the riser. This would have originally held cloth stretched over the "window" spaces, but I think the organ looks better without that (it was probably removed by Carl Frei - or earlier). On the frame is mounted a set of lead tubes. These carry the impulses for operating the drums. Note how the single tube (for the bass drum) from the right side runs to the left, and the double tubes (for the snare drum) from the left side run to the right. The organ, originally had the keyframe mounted either in the back or at one end with the music card passing along the length of the case through slots at each end. This resulted in the two stacks of music standing at opposite ends of the organ. At some point in the past, the keyframe was turned through 90°, but there would have been no room for the bass drum beater at that end, so the drums were swapped.
I also noticed that the chest is fitted with enough channels for registers, despite being made for an organ without them. The design and layout was evidently universal for both models.