Re-using Organ Tabs, making them momentary.

[Bassman]

Here is a little tip for organ midifiers. If you are tired of wasting old hardware because the tabs are not suitable for midi use, i.e. they are not momentary, they are changover switches, then this little tip might save you a lot of trouble. These typical Tabs can be made momentary quite easily. And, as they are usually semi-transparent plastic, you can light them from underneath at the same time.

So take your tabs racks out of the organ, and you will see they all pivot on a long pin.

Pull this pin out slowly and remove each tab one at a time and set aside so as to remember the order (if neccessary). Nothing will spring out and get lost.

Turn the rack over and you will see the little spring located in a hole. About 1/2" from this you will see, among many others, another hole in line with the spring hole. Sometime they have posts fitted which have to be removed, a little patience doing this, otherwise the board will break.

Take a 1/8" drill and enlarge these 'new' holes.

N.B. While you are at this, you can drill holes in the frame under each Tab to take LEDs. Most of these tabs are semi-transparent, and if you use bright white LEDs they will light up the tabs and look great when finished.

Now get a small flat nosed pliers, the ones with teeth, and grip the spring by two coils as close the locating hole as possible. Lift the spring out of it's hole and place in the new hole that you have enlarged. Repeat this all along the tabs.

Re-assemble the tabs on the pivot rod, one by one, in reverse order, and now you have momentary Tabs, that will illuminate (once you've done the wring etc.) when pressed. All you need to do is choose suitable contacts for each Tab. Some are break, some are make, the latter are the ones you need.

Also you will help the environment by not trashing perfectly usable hardware.

good luck

Bassman

[stryd_one]

Nice document!

[Per S]

If you are tired of wasting old hardware because the tabs are not suitable for midi use, i.e. they are not momentary, they are changover switches

This is an interesting comment.

The vast majority of organs, theatre or classical, real or electronic don’t use momentary stop keys. My own organ, a theatre type, has stop keys that are either on or off, you flip it and it stays. I used the MIDIO128 application to midify the entire organ, ideal for this purpose.

Personally I can’t see the advantage of modifying the setup as shown but I may be missing something here.

[Bassman]

Hi Per S,

No I don't think you're missing anything, I just came up with the simple mod, and thought it might be useful to somebody.

It isn't neccessary, as you say, 'on' sends a message and 'off' sends a message. I doesn't really matter if the switch stays on in between, however long that is, providing key 'repeat' is disabled.

But you don't need to mod every stop, you might need just a few stops/tabs to not flip and stay.

bassman

[StentorVox]

Well done, Bassman.

Although I will never use this particular applicaion,

what is significant here is the way fellow-posters

are willing to experiment and document a variety of

applications for MidiBox and share with the forum.

Before I discovered this list I spent several years

in lonely experimentation to create some way to

meet my particular switching applications.

All of us can pick up a hint here and there, and

benefit from such graphic documentation  as you

provided, even if we don't follow it to the letter.

PK

[Bassman]

Thanks PK,

I'm suitably encouraged.

bassman