Hi @jflee! Sorry you are having difficulties.
I’ve had only one other report of the triggers on production units not working with a particular module - it was Buck Modular’s Drumfuck. I was able to verify this with my own DF as well. I was able to make it work by simply passing the trigger through a buffered multiple.
This was a little perplexing as I had tested the crap out of the TXo over the last year with the DF (I had one of Skyler’s early prototypes). I then went and re-tested a production TXo with the 25+ modules (list at bottom) that I used to verify my prototype trigger outputs and found only one other that wasn’t triggering - the Tsyklon Labs Chaos Divider. (This was also frustrating as I had helped Frank with the build doc and tested the prototypes extensively with it! )
Just prior to my big build, I reviewed the circuit with @Galapagoose to make sure that the TELEX wouldn’t be harmed by the RUN jack of early Just Friends modules that hadn’t been modified. We made a slight change to increase the resistance on the trigger outputs to make things super safe. If you are looking at the circuit, we upped R102, R103, R104, and R105 from 1k to 10k.
I know that this additional resistance dipped the voltage a little under 5V. This value still is way over the 3V recommended by the unofficial Doepfer specification. However, your voltage seems lower than I would have expected. The TXo in my portable rig runs at close to 4.585V for every trigger when on. Is there any chance that your case is experiencing power issues?
A theory would be that the change to 10k dipped the voltage enough that some modules that are based on 5V microprocessors with certain input circuitry don’t like the output triggers anymore. It is odd because I have a number of other 5V microprocessor modules that are happy as clams with the TXo. So, maybe not - especially considering some of the evidence for the next theory.
Another theory would be that there is something about the change in impedance that some modules don’t like. That may be why, in your situation, 3V gates still work but the higher value gates from the TXo do not. This may also be why that my experiments show that going through a buffered multiple solves the problem with the aforementioned DF and CD.
I wonder if swapping back in 1k resistors for R102-105 would solve your situation? Or, is it a power thing?
Anyone else have thoughts? It’s clearly not a widespread problem - but one that I’d love to fully understand.
FYI: these modules all tested out fine with triggers from a production TXo in my home rig: Teletype, Peaks (in Drum Mode), LDB1 (Little Drummer Boy), Braids, Rings, Grids, Turing Machine, Erica Synth Pico Drums, 4ms Dual Looping Delay, Make Noise Tempi, 4ms Pingable Envelope Generator, 4ms Shuffling Clock Multiplier, 4ms Rotating Clock Divider, Ornament + Crime, Bitbox, Bastl Grandpa, Bastl Tea Kick, Make Noise Erbe Verb, Make Noise MMG, Make Noise Optomix, Make Noise Function, Intellijel Quadra, and Neutron Sound Orgone Accumulator.