Yes, that’s the one I use daily.
It states “maps the PARAM values for input x across the range y - z (defaults 0-16383)”, and I misunderstood it thinking it was mapping INPUT (as “hardware input”) x across the range y-z.
My bad. Thanks !!
I finally got my DIY TXi to work, forgot to connect the grounds on top of the PCB….
I can confirm it works perfectly fine with a Teensy 4.1 which is more readily available atm than a 3.2. Massive overkill for this module but it works 
I’m using the new drum ops to turn teletype into a master sequencer for my live techno setup and the TXi allows me fine control over all kinds of parameters, loving it!
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How did you find the soldering? I have the TXi panels coming, and I’m somewhat dreading soldering it up.
Yeah I did it the painful way with an iron with a fine tip. Just found out the parameter knobs are working but strangely the ins aren’t, the keep yielding -16383…. No idea why but I am happy enough having the param knobs, wasn’t going to use the ins. Still very strange to have only half the module working….
I was planning on using an iron too. I’m assuming the non-painful way is to use a reflow oven?
I also really just want TXi for the encoders. I’ve been looking at the Michigan F8R, but the footprint is just too big for how I’d use it, and 4 encoders/sliders are all I’d really need.
Dewb
1843
The MCP6004 op-amp IC is used for the ins but not the knobs, so I’d re-inspect that part of the circuit.
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Just wanted to mention that a fine tip for smd parts is a good start but I found using fine solder very useful.
The kester I have used is .40mm, if I used .8 it would be far too much.
staysh
1845
There is a chance the calibration data could be messing up your values. The last step in reading the inputs is mapping it to -16384 to 16383 even though it’s only a value from 0 to 16383 to start. If the calibration data was wrong, I could definitely see that causing some issues. The “one above” some number seems like some artifact of an integer operation to me.
Maybe SerialPrint() those values sometime at startup to double check? If for some reason the low one wasn’t that low, the mapping might produce something funny.
A CV of approximately -10V should produce the -16383.
The CV goes into an inverting amplifier so a strong negative signal will produce a higher reading (towards 8192). Which is then multiplied by 2 and subtracted from the max to have large negative voltages around 0 and positive voltages (originally 0) around 16383.
From there its mapped across -16384 to 16383.
So if everything is working right in the firmware that means you have -10V at the input of the MCP6004 or something else that is making the voltage swing to the rail. I’d check and make sure R108, R107, R111, R112 are indeed 200k. If those are smaller you could be sending in too strong of an offset.
If the all of the voltages aren’t changing at all, that is curious. As @Dewb said, I’d double check the MCP6004 is getting appropriate power (pin 4 and 11 should have continuity with the 3.3V and GND respectively.
Also that pin 3,10,12,5 of the MCP6004 have continuity with ground.
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saiiils
1846
Is anyone still building TXo’s? I’ve been looking to get my hands on one for a bit. I’m down to try building one myself, but I haven’t tried SMD soldering yet. Might get some full-kits from NLC to try before attempting the TXo.
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I’ve been trying my hand at a few simpler SMD builds, hoping to get good enough to do a TXi.
Results so far do not leave me hopeful.
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I’m glad to see @kauwgomboom was successful with a Teensy 4.1-based TXi. I have a Teensy 4.0 that I would love to build into a TXo for use with crow. Am I in for a world of pain if I try it? My understanding from upthread is that the i2c library was the main blocker but if the 4.1 TXi works well, maybe that issue has been cleared…?
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Well I celebrated too early, I’m having a lot of trouble with stability, it just looses track of the param knobs stops responding. I’ve had so much trouble that I’m just building a Tesseract Sweet 16 now to be done with it 
oof, that’s rough. I hope you have better luck with the sweet 16!
I’m about to start building a TXi and TXo. I have the helper for the TXo, and was hoping to try a Teensy 4.1. Reading the thread this seems possible. Am I setting myself up for disaster? And do I have to do anything special to get this to work? I am no incredibly experienced in this stuff, but I did successfully build a Terminal, and I’ve done quite a bit of through hole DIY projects.
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Thhhh
1852
So, how are people doing w/ Teensy 4s these days? Are they a viable replacement?
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saiiils
1853
Hi, so I had a friend help me build a TXo.I was wondering what the startup behavior should like like when the module is powered on? Also what should the Teensy light look like when it’s powered on and working?
Can’t speak to the undercarriage, but my TXO does nothing upon turning on my case.
Outward facing LEDs are only reactive when signal is being sent.
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saiiils
1855
Built a TXo and I’m not getting any outputs nor LED feedback anywhere. I was poking around with the multimeter and I was not getting any readings from the digital outs (pins 4-7) from the teensy when I execute TO.TR.TOG (1-4) on any of the digital outs. Anyone have further troubleshooting tips?
I got sidetracked building a Nava 909. I’ll get back to this soon and will report back, but further up in the thread, the member who initially report success with a Teensy 4.1 ultimately had issues and bagged it. So I’m not holding my breath.
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Thhhh
1857
Worth noting: I just got a mail from Mouser saying that 3.2 is now officially marked as obsolete.
New edit:
So, I got a lead on a 3.2, going through the BOM to see what I can find on Mouser.
I am currently missing:
OPA4171, specifically 595-OPA4171AIDR. Can this be swapped safely for 595-OPA4171AID?
The 15k film resistor, 667-ERA-3ARW153V, is missing. Is it just an ordinary film resistor? Any advice for replacement parts?
MCP1703AT-5002E/CB, I cannot find. Or, on backorder. Any good replacements that are readily available?
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