The electrical contacts oxidize , requiring periodic cleaning. Motors require periodic lubrication and removal of dust that tends to clog the cooling vents. Belts gradually stretch, requiring periodic adjustment and eventual replacement. Older organs have electron tubes in them. The life of a tube will be lengthened if the layer of dust is removed.
Dust acts as an insulator, holding the heat inside the tube.
Tube pins and sockets need periodic cleaning, too. Many problems in tube organs are related to oxidized high-voltage pins and sockets, and switch contacts. I recommend an annual preventive maintenance plan which includes removing all tubes, then cleaning the glass surfaces, pins, and sockets, and all the switch contacts. Periodic maintenance has been proven to reduce the number of malfunctions in any electronic organ. The octaves were created by dividing the source pitch in half as many times as necessary to produce the full range of the instrument.