TM3030 freezes upon receiving multiple MIDI notes at once

[speepbibu]

Hey all. Just a quick reply to say that all signs are pointing to the octocoupler. The problem was getting progressively worse. I ordered new ones and I’m waiting to update once I see if that’s the issue. If that doesn’t work I’ll shoot over the midi code. I have a Mac and figured I’d wait and see if it was the easy fix first. Will let you know when I have more answers!

[speepbibu]

Colin is on the case but he needs to know what the Octatrack is sending out to make sure it's not doing something peculiar. Can you record the midi output of the Octatrack?

Hey! So after a week of shipping delays I finally got the 6n137's in. No luck. I think it improved a bit but who can say. So, I downloaded midi monitor (I have a mac) and started recording information. I saw a CC information that didnt need to be sent, so I turned all of that off. It could handle a bit more before it crashed. I think that explains why it was a bigger problem on some patterns more than others. If I turned clock send back on it crashed easier. It seems like at some point the midi hits a threshold and then stops sending or receiving entirely. It freezes and doesn't trigger the note off. As far as what I can capture on my midi monitor, there's note on and off, any cc information, velocity, and time code per channel. I may not be able to see the depth of info you're asking for with this program. I'm going to turn after touch off on my midi controller and make sure there aren't any unheard CC's being sent, because that seems to help the most at this point. Honestly, I feel like its a good limitation lol. It helps me focus on the song. That being said, I'd feel better performing with it if I had solved this problem. I attached a screenshot of the Midi Monitor feed. The Tm3030 is on channel 1. If you have any other ideas let me know. Thanks a lot!

[Synthbuilder]

The problem was getting progressively worse.

I wonder whether the crystal oscillator of the PIC is not running at the right speed.

Firstly, check that the digital supply is close to 5V. This is most easily found by measuring the voltage across C8.

It may also be worth inspecting the board around the pads (both on the underside and the top of the board) of X1, C1, C2, and pins 9 and 10 on the PIC. Make sure there's no residual flux or other grime there. Indeed, it could be a good idea to wipe down that part of the board with a bit of iso-propyl alcohol on a cotton bud.

If that doesn't work, I'd be tempted to replace C1 and C2 in the first instance, and then maybe X1.

[speepbibu]

Sorry, the problem isn’t getting progressively worse. I was under the impression that it was, but the octatrack was just sending CC on midi tracks that I had just forgotten about and didn’t need. The pattern I was working on had a lot of them so it crashed more than usual. Once I fixed that it crashed the same amount it always had. Also, while it hasn’t stopped crashing, the issue of dropped notes and irregularities has improved with the firmware update and new octocoupler. I will do the troubleshooting you outlined and update you. Just wanted to say that quick. Thank you!

[speepbibu]

The problem was getting progressively worse.

I wonder whether the crystal oscillator of the PIC is not running at the right speed.

Firstly, check that the digital supply is close to 5V. This is most easily found by measuring the voltage across C8.

It may also be worth inspecting the board around the pads (both on the underside and the top of the board) of X1, C1, C2, and pins 9 and 10 on the PIC. Make sure there's no residual flux or other grime there. Indeed, it could be a good idea to wipe down that part of the board with a bit of iso-propyl alcohol on a cotton bud.

If that doesn't work, I'd be tempted to replace C1 and C2 in the first instance, and then maybe X1.

Hey! Still working on this and wanted to update. I measured the voltage across c8 and got a steady 5v. Even measured during and after a crash and that didnt change. I cleaned all the flux I could see but I was still getting this problem. So today I replaced c1, c2 and x1 to some effect. It seems like it's more stable but I'm still getting a crash if theres too much note information on any particular trig. I really feel like it has something to do with note on and off information bleeding over from other channels somehow. I truly have no idea how this works, but the only consistent thing I'm seeing is that if too many notes are triggering on at a certain step, the TM3030 gets overwhelmed and will not turn the note off.

[Synthbuilder]

... the TM3030 gets overwhelmed and will not turn the note off.

One more thing to try is to check and possibly replace R1 and R4. These should be 220R and 1K respectively. These are the resistors that surround the opto-coupler. It'll also be worth checking the opto-coupler's protection diode, D1. That should be a 1N4148 and be orientated correctly.

Tony

[speepbibu]

Hey!!! I got it working! I replaced some caps, put in another new octocoupler and redid the firmware update again. It’s smooth sailing now! I’m so excited. I probably just didn’t do the firmware update correctly the first time, although I’m not sure what I did differently. Or maybe it was a combination of all things. Either way thank you so much for your support. I’m so stoked that this think is working now it’s such a wonderful synth.