Midi Box Troubleshooting

Hi. I’m looking for some help troubleshooting a midi issue I’m having. I’m using an MC8 connected to a Morningstar Midi Box, with only those 2 devices in a midi loop. Connected to the Midi Box I have 2 ML10X’s, Strymon Timeline, Source Audio EQ2, Chase Bliss Habit, and Empress Zoia.
Everything was working perfectly yesterday. Not sure if this is relevant but I did a little bit of rewiring yesterday, but only to add the Zoia to an ML10X loop and plug it in to the Midi Box, and to adjust some of the loops between the 2 ML10X’s. Didn’t touch any other midi connections.

When I started to program some of the midi stuff with the Zoia I noticed the Timeline wasn’t responding to midi. I checked the midi channel, checked the cable with a multimeter, restarted the Timeline, turned my whole board off and back on, nothing helped. Then I noticed the Zoia also didn’t respond to the only midi command I had programmed (engaged or bypassed). The Habit is working flawlessly, both with PC commands for patch changes, and CC commands for tap tempo, on/off, and expression.

I checked the signals out of the MC8 with the editor’s midi monitor, all are working perfectly as programmed.

After some unsuccessful troubleshooting attempts like putting the timeline in a different output on the Midi Box (nothing changed) I noticed the Zoia had started working, although I hadn’t changed anything with its setting or output. A few clicks of my button assigned to engage/bypass the Zoia worked, and then stopped working. Then I noticed the EQ2 behaving in the same way, repeatedly clicking the button assigned to a preset on the EQ would work for a few clicks, then stop working, then come back again a few clicks later. Then I checked the ML10X’s, they had stopped working too.

To make things weirder, after writing the first paragraph of this message I checked it all again and it all worked flawlessly. Just checked it again now and it’s back to random behaviour. Didn’t touch anything in between.

The reason I suspect it’s a Midi Box issue is that the blue light that flashes when a signal is being sent or received has been very bright and noticeable, today it is sometimes dim and sometimes back at full brightness, although this doesn’t seem to correlate with the messages being sent or not, ie the Habit still works perfectly whether the light appears bright or dim.

Anyone else had a similar issue? I’m absolutely stumped as there seems to be no changes I can make to fix it or to even isolate the issue, it will just be perfect one moment and not working the next.

TLDR - Midi Box is working perfectly for only one pedal, sporadically for others, despite no changes being made between it working or not.

Thanks all.

UPDATE: I found the problem although I’m not sure why it’s a problem.

I was using a 3.5mm TRS cable between the Zoia and the Midi box, but it was a cable I bought a while ago as an audio or headphone cable. As the Zoia and Midi Box both use 3.5mm TRS I thought it would be perfect and save me destroying more midi cables just to solder up the same thing. After I unplug this cable everything is back to normal so I have no doubt it is the issue.

I’m still wondering; is there a difference between an ‘audio’ TRS cable and a ‘midi’ TRS cable? I asked the guys at my local electronics store and they just said “TRS is TRS” while giving me a confused look. So I thought it was a dumb question. I’ve tested the cable and it works exactly as you’d expect.

Happy I found the issue but still feel in the dark as to what the actual problem was…

There’s no difference at all. It’s all just TRS cables with 3 contact points (tip, ring, sleeve). Audio might have thicker gauges but that won’t matter at all.

It is likely that the tip/ring/sleeve is shorting together in your DIY cable. Do you have a multimeter to check the cable connections?

Yeah I have a multimeter, very thoroughly checked it and the connections seem fine. Maybe it just gets on an awkward angle when I plug it in. I’m very new to soldering so no doubt it’s my dodgy workmanship.

Not sure if you have checked this, but check the Tip and Ring connection with the multimeter. i.e. make sure tip isn’t shorting to ring, and tip/ring isn’t shorting to ground.