Using extra stop tab as a switch

[tschnuckel]

Our church just got a Klann Cymbelstern gifted to them. I've been charged with installing it.

We have an extra stop tab on our Allen. Can I some how use it to turn the cymbelstern on-and-off? I don't have a diagram of the stop action. Maybe this question would be more clear if I did.

The motor draw is 83mA on 12-24VDC.

[tucsondave]

What model Allen?
Is there a USRD-2 board installed?

td

[tschnuckel]

MDS-25
There is a USRD2.

[tucsondave]

Perhaps these will help. Maybe one of the blank tabs will activate an unused output on the USRD-2 board.
Note that they switch to ground.

td

mds25-gc-io-1.pdf
USRD-2 Schematic.pdf
USRD-2.pdf

[jbird604]

A zimbelstern typically has a 12 volt relay, polarity doesn't matter, and the relay pulls in to switch on 120 volts AC to a little motor. There will be a pair of screw terminals to attach a zip cord to (with spade lugs). Run the zip cord to your organ and provide a way to send 12 volts on one conductor and ground on the other.

In a pinch, you can use the "Main Off" of the antiphonal switching to activate the zimbelstern. Remove the wire that is on the "Main Off" screw of that relay, and attach it to one of the two control wires coming from your zimbelstern. Attach the other control wire to a +12 volt screw (there will be one on the antiphonal relay). Now, when you flip the "Main Off" tab, the zimbelstern will come on. Why? Because when you flip that tab, the MN board tells the USRD board to ground out the wire that is connected to "Main Off."That completes the circuit, and the relay in your zimbel will turn on the AC voltage to the motor.

This assumes that you don't ever use or need the "Main Off" function, as many folks do not. If you do, you'll have to come up with another solution.

- - - Updated - - -

See what Dave posted above. He's a good man. You can tell because he and I are always posting at the same time on the same threads! He must be younger than I am because I don't have the energy to look up all these things and post them any more!

[tucsondave]

See what Dave posted above. He's a good man. You can tell because he and I are always posting at the same time on the same threads! He must be younger than I am because I don't have the energy to look up all these things and post them any more!

j,
It's not that I'm younger it's that, like many organ techs, I don't have a life! :-)
Could also be that I was born 9 months after the Roswell landings...er, I mean crash. We, I mean they, are not here to colonize Earth, just make organs work better.
To Serve Man

td

[tschnuckel]

Just so I understand, the actual stop tabs don't really switch anything. It signals to a circuit board to do do something.

I thinking I've got a plan. Will post with results.

[tucsondave]

Correct. The tabs simply control serial data. There is no switch on the tab that can be used. If there is no output from the USRD-2 board available then the other option would be to mount a reed switch on the stop bracket so it would be activated by the magnet on the tab.

td

[tschnuckel]

The stop I want to use (#50), controls a spare wire (white) from the USRD-2 to underneath the cage. There is another wire (black) paired with it. I was excited to think the USRD wire was ground and the black was positive. The black wire actually comes off of a ground terminal on the top of the cage.

The attached sheet Trem IV.pdf shows the black wire from the cage is indeed ground. What is the reason for taking a ground from the cage and tieing it to the PS and chassis for the Trem IV? Ground loop?

Ok back to the Zimbelstern. So I'm going to take the ground from the Stop controlled USRD wire (white). Does it matter where I get my positive from? Can I grab any 12v from the card reader supply or 15v from the top of the cage?

[jbird604]

I think you are onto something. Grab your +12 from the 12 volt supply in the floor of the console. Orange wires generally carry 12 volts in Allen consoles. You can check with a meter to be sure. It's an unregulated 12 volts, so it might run closer to 15 volts without a load on it. The same supply also feeds the card reader lamps, but the voltage supplied to those lamps is regulated and adjustable and has its own screw terminal. Don't use that one because it will probably be set at around 8 volts to properly supply the card reader lamps.

Use a meter to verify your idea before you get too far. Clip a lead to the orange +12 wire and another lead to the stop-controlled white wire. Draw the spare stop and see if you read about 12 to 15 volts. If so, you have your zimbelstern control.