All church organs have pedal claviers. Pedal pressure can be precisely adjusted so all pedals require the same amount. Spring tension changes with age and use. Many circuit boards have edge connectors to plug them into sockets. I see a lot of problems associated with corroded edge contacts .
Power Supplies create the precise voltages necessary for the different electronic subsystems.
Some cannot vary more than one-fourth of one volt without causing damage to sensitive electronic parts. Like oscillators, they drift, eventually creating confusing or intermittent problems. Also, power transistors and ICs, which generate heat during operation, will last longer when not coated with an insulating layer of dust. Most organs employ a computer-type memory system to hold registrations. Most of these systems require a backup battery to sustain the memory circuits in case of a power failure.