Register changes are activated by holes in strategic positions on the music card. The impulses created need to be remembered to keep the required registers operating. The "memory" for this is the Register Box. The VB scale has provision for four registers, but for some unknown reason this particular organ has only three. The register box, therefore, has three latches which hold the registers on. The registers are all cancelled together by physically pushing the latches out.
This small item is quite intricate, as shown in this picture of its constituent parts. The three pallets, six puffs, nine springs, and three latches all received careful attention, and the box re-assembled and sealed with new gaskets. It was then mounted back in its position and connected to its wind supply, and tested.