After working on both Pipe and Electronic Organs for over 60 years, I utilized the original contact blocks (7) with 4 contacts shorted together for keying and the other 3 connected to Common, with the original silver shorting bars, and after cleaning all Sterling Silver contact surfaces my organ played very well for about two years, then I started having dead and intermittent keys. For another two years I used Deoxit D5 on the troublesome contacts using the extension spray tube. This worked well for a while and then other notes went missing. I decided to do something.
I checked out several methods, I had had problems
in the past with magnetic switching, that has been used on many modern organs, so I decided to order a few Optical switch devices, after much testing I decided to build a batch of 12 note circuit boards, with these Opto-Switches, After wiring them to my midi encoders and adjusting them, I have now been using them for the past eight years with not even one problem. When you first play using Optos, you will actually feel the positivity when playing !
I have a few photos of my system that I will send to you if you DM me your Email address, and feel free to ask me any questions !
There are also devices known as "Hall Effect Devices", with care in installing them, and their small associated Magnets will work reliably also. I intend soon to experiment with them if they are not to expensive ! Mel