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[BobTheBob]

Hi Guys,

I know some of you have seen this all before, but I have midi issues with my controller footswitch and my MP-1. I'm reading through some of the self-help here, so I've got a few things I can do, but I'll describe my problem.

I have a Tech 21 midi moose controller with a 7 to 5 pin converter cable (midi moose has phantom power on pins 1 and 3). When I used it with a standard 5 pin to 5 pin cable it worked fine. I then started using the phantom power supply through the new converter cable, and I'd notice that upon hitting a switch on the controller, it would just lock the MP-1 interface - no buttons would do anything. I tried going back to the 5 pin only cable, and that worked intermittently, and now that doesn't work at all either.

I'm going to try if the midi-thru works with some other midi devices and report back. Any additional help would be appreciated.

Cheers!

(BTW, my MP-1 is v1.38 if that makes a difference)

[rnolan]

Hey Bob.  I haven't seen this particular setup/issue before.  So after a bit of research i.e. what pins are connected and what do they do my suspicion is (based on the locking up) is it's to do with the 7 to 5 pin cable wiring.  So in standard 5 pin assignments (https://learn.sparkfun.com/tutorials/midi-tutorial/hardware--electronic-implementation) pins 1 and 3 are not used.  Thus your foot switch uses them for phantom power connection (as it says in the manual).  The MP-1 7 pin connector uses pin 6 & 7 for phantom power.  So if you use a multi meter to check continuity/connectivity of the cable, you'd want pins 6 & 7 to be connected to pins 1 & 3 on the 5 pin end and pins 5, 4 & 2 to be connected between the 7 and 5 pin plugs (pin 5 is data, pin 4 is 5v power (for hi/low switching) and pin 2 shield).  As far as I can tell (see attached) the MP-1 7 pin connector only uses pins 6 & 7 for phantom power and pins 5 (data) and 4 for 5v power for switching.  Pin 2 doesn't seem to be connected but may be connected to ground (shield)  .  If the cable is fine i.e. pins 6 & 7 > pins 1 & 3 and pins 5 > 5, 4 > 4 and 2 > 2 and no other cross connections it should work.  If for some reason 9v power got cross connected to MP-1 pins 5 or 4 or 2 it may have damaged the opto-coupler/isolator, or it may have died (I've had one (opto-isolator) die before in a MB-1).  So based on (I tried going back to the 5 pin only cable, and that worked intermittently, and now that doesn't work at all either.) I suspect the opto-isolator needs replacing (U10 on the schematic attached).  MJMP sent me the part and IIRC it was an easy swap as it has a chip socket on the PCB. 

Being v1.38 makes no difference, the later EPROMs v2.00 and 2.01 (which was the last available) add some sysex program dump and load capability and additional factory presets.

[BobTheBob]

Thanks for the reply, mate. I tried some of your suggestions and discovered the following:

- Continuity was fine in the converter cable; pins 6 and 7 were correctly linking with pins 1 and 3, with pins 2,4 and 5 correctly connected.
- I tried the midi moose with my old D50 synth and it worked fine (9v PSU attached to the midi moose - see noted behaviour below).
- I then tried the midi thru on the MP-1 to the D50 and it also worked fine (9v PSU attached to the MP-1), however it also was working on the MP-1 too!

Having performed the last two steps above, the midi on the MP-1 now appears to be functioning as expected. I have no idea why that would have any effect and why it has "fixed" the issue. One thing I did note with the second step above, is that the first time I hit a switch on the moose when attached to the D50, the D50 would read "Midi communication error" (or something like that), but subsequent selections didn't show this error and changed the patch accordingly.

Well, the problem has righted itself for now, but I suspect it may rear its ugly head again in the future; watch this space.

Thanks
Bob

[BobTheBob]

Well I had a play today and the midi was busted again - just freezing the preamp controls when I first pressed something on the controller.

I took the covers off the MP-1 and wiggled the grey ribbons going to the output board to make sure everything was seated correctly, plugged it back in, and it seemed fine again.

I'll let you know if anything else happens, but this is a little weird.

Bob

[Harley Hexxe]

I never did trust the 5 to 7 pin conversion plugs.

If I were going to use one of the ADA MIDI controllers, I would hook it up with the ADA wall wart in the back of the preamp and a 7-Pin cable to the controller. Everything else, I used a 5-Pin cable for.

When I connect my MIDI gear to my Voodoo Labs Ground Control pedal, I phantom power that pedal by way of a GCX, then 5-Pin MIDI cables to everything else, including the ADA gear. I've never had a problem with either set up with program changes or continuous control,(aka Real Time MIDI in ADA nomenclature).

That's probably not much help in your situation, but I wonder if there's another way to phantom power your controller. I'm not familiar with that one at all, but I'll try to look up some info at their site.

Harley

[rnolan]

Hey Bob, well good that you got it work (albeit with some weird issues) and the cable is fine.  Given the initial result with the D50, it implies some initial MIDI handshake issues?? I wonder if power on sequence makes a difference?

[BobTheBob]

I never did trust the 5 to 7 pin conversion plugs.

If I were going to use one of the ADA MIDI controllers, I would hook it up with the ADA wall wart in the back of the preamp and a 7-Pin cable to the controller. Everything else, I used a 5-Pin cable for.

When I connect my MIDI gear to my Voodoo Labs Ground Control pedal, I phantom power that pedal by way of a GCX, then 5-Pin MIDI cables to everything else, including the ADA gear. I've never had a problem with either set up with program changes or continuous control,(aka Real Time MIDI in ADA nomenclature).

That's probably not much help in your situation, but I wonder if there's another way to phantom power your controller. I'm not familiar with that one at all, but I'll try to look up some info at their site.

Harley

Good to note that, thanks. I don't think the phantom power is the issue here though. Luckily it seems to be stable now.

[BobTheBob]

Hey Bob, well good that you got it work (albeit with some weird issues) and the cable is fine.  Given the initial result with the D50, it implies some initial MIDI handshake issues?? I wonder if power on sequence makes a difference?

The power on sequence did cross my mind and I tried a bit of ad-hoc experimentation, to no avail. However, after wiggling the grey ribbons, things seem to be ok now - fingers crossed.

[Dante]

Great band name; Wiggling the Gray Ribbons

[Harley Hexxe]

Great band name; Wiggling the Gray Ribbons

Better than "Whipping A Ball With A Snake" (?)

[MarshallJMP]

It "could" be that the midi mouse is sending odd midi messages which messes up the mp-1. I'm going by this because you had a midi communication error. Now just guessing here.

[BobTheBob]

It might have been, but I haven't had it since which is strange. Thanks for the input though. I'll let you all know if it rears its ugly head again.