Motion Sound footswitch for Mojo - troubleshooting

[SamuelBLupowitz]

I've been using the two-button stop/run & slow/fast footswitch for my Motion Sound KBR-3D as a footswitch for the Leslie sim on my Mojo XT during rehearsals (back when I was having band rehearsals). The only catch is that the way the Mojo receives the pedal signals over the TRS cable, the sim swaps the button functions, so that the slow/fast button stops the Leslie, and the stop/run button changes from slow to fast.

 

I've been doing some pedalboard rearranging during quarantine, and it's a physically improved layout now, but I would love if I didn't have to swap my brain around when using the onboard sim, or flip the footswitch upside down during rehearsals, becuase that changes the way I have to run the cable. Someone over at the Crumar/GSi group on Facebook said I just needed to swap the tip and ring. I have one of the old Ashby Yamaha-FC7-for-Roland-keyboard adapters hanging around from my days of gigging a Roland VR-760, and I thought that switched the polarity by swapping tip and ring... but when I use that adapter, the "slow/fast" button does change the "slow/fast" light on the Mojo, but the Leslie is always stopped, no matter what footswitches or buttons I press. The Leslie only runs if I hold down the "run" button on the Mojo control panel, which, obviously, isn't a real solution.

 

So I guess I have two questions, with the more crucial one being the first:

1. How do I flip the signals from the Motion Sound pedal so that the Mojo recognizes them correctly?

2. Does the Ashby Solutions FC7X-ii adapter work by swapping tip and ring, or is it doing something else?

[vonnor]

Markyboard might be a good information source for this issue. I know he has made conversion cables in the past.

 

Would be easy to test with an ohmmeter or circuit tester though. Just see which loop closes/opens when you press each switch. Only 3 possible loops:

 

1. tip - ring

2. ring - shield

3. tip - shield

 

Find the contact that is common to the two loops that change while pressing the switches (tip, ring, or shield)

Swap the other two contacts.

 

Assuming there's nothing squirrelly going on inside the MS footswitch.

 

~ vonnor

[Markyboard]

Hi Sam-

 

First I would say it was just by luck that your dual footswitch worked at all with the Mojo - so cool. I'm not surprised that swapping the tip and ring didn't just reverse the function of the switches (and btw yes to question # 2).

 

I would guess that those 2 switches are different; maybe a single pole single throw (spst) and the other a single pole double throw (spdt) switch. With 2 of these switches you have 4 configuration possibilities. If you have an ohm meter you can look at what the tip and ring are connected to with all 4 possibilities and maybe make a modification. But chances are you'll have to actually swap the switches themselves.

 

Hope that make sense.

 

Edit (I see Bill beat me to most of this with his spot-on reply)

[SamuelBLupowitz]

Very helpful, thanks Mark and Bill! I'll see if I want to dig in deeper... or just suck it up and flip the footswitch around when I'm using the built-in sim.

 

Slightly related, I learned a great German word from a colleague the other day: "verschilmmbessern," which roughly translates to "making something worse by trying to improve it." I'm wary of verschilmmbessern anytime I deal with anything vaguely electronic, particularly since that one time I lubricated the sticky key action on my Wurlitzer and wound up shorting out the amp so it stopped producing sound.

[Markyboard]

Slightly related, I learned a great German word from a colleague the other day: "verschilmmbessern," which roughly translates to "making something worse by trying to improve it." I'm wary of verschilmmbessern anytime I deal with anything vaguely electronic, particularly since that one time I lubricated the sticky key action on my Wurlitzer and wound up shorting out the amp so it stopped producing sound.

 

In the electronics world we know that as the Initiation or Rite of Passage phase. The thing most people don't realize is there's only one phase.

 

[Doerfler]

Slightly related, I learned a great German word from a colleague the other day: "verschilmmbessern,"

 

word of the day.

[SamuelBLupowitz]

Interesting update: if I unplug the footswitch (with the FC7X-ii) and plug it back in while the Mojo is turned on, it seems like the Run function will turn on from the control panel. Then the footswitch works as designed. It requires double-taps to change functions, but that still requires less rewiring of my brain than angling my foot differently.

[Markyboard]

Ooh - be careful. I seem to recall words from GSI not to do this. It never made sense to me and maybe they eliminated the issue or backed off the concern. Quick email should do it - they (Andrea) are very responsive.

[SamuelBLupowitz]

Final update on this â Andrea sent along some useful info about how the switches work in the Mojo, but then the next time I powered it up, the footswitch worked just as it should! I think the way the switches are set when the Mojo powers up makes a difference, along with the adapter. Works like a charm now.

[Markyboard]

Hey Sam - Glad you found a workable solution. Would you mind sharing the details Andrea provided here or via PM?

 

Thanks.

[mate stubb]

On my Mojo dual, the half moon switch has a quirk. It has 3 positions, for stop, chorale, and tremolo. These states roughly correspond to tip/sleeve connected, ring/sleeve connected, and none connected (I probably have that order wrong, but it's not important right now.)

 

The point is, if the half moon happens to be in the position of none connected on power up (I think it's stop), the Mojo can't detect that a switch is hooked up.

[SamuelBLupowitz]

if the half moon happens to be in the position of none connected on power up (I think it's stop), the Mojo can't detect that a switch is hooked up.

Yes, that sounds like it jives with my experience.

 

Here"s what Andrea sent me:

The footswitch for your mojoXT should be cabled in this way:

 

left footswitch - momentary only - shorts sleeve with tip - start/stop

right footswitch - momentary only - shorts sleeve wih ring - slow/fast

 

and yes, the two pushbuttons in the panel are connected in the same jack pins used for external accessories, this means that with footswitch you can use both panel and jack, if an halfmoon is connected, pushbutton on panel do not work because halfmoon is latched.

If you connect something there while the instrument is on, there's the possibility to connected tip-ring-sleeve for a second while inserting, that's why you will see leds on buttons going on or off.

 

You can't use latched footswithes on a footswitch for your MojoXT.

[Delaware Dave]

".. You can't use latched footswithes on a footswitch for your MojoXT.."

Wow, didn't know this.