Hi Segu, It's been a while, but I THINK there was a difference in the BOM for the version 2.1 build from the 2.0 build. I had the 2.0 PCB's but could only find build documentation for the 2.1 version. I contacted Befaco directly and they were kind enough to provide me with the correct build docs, an...

I've sent sent a request over a month ago to them to refund my pre-orders for the sequencer and have not heard back, so I would be cautious. Ordering from a 3rd party such as SynthCube sounds like a good idea to me. FWIW, I'm guessing that the Behringer System 100 modules wouldn't be too far off fro...

MikeDB wrote: ↑

Sat Sep 19, 2020 2:18 pm

A few slight differences but gate cut-off voltage same so give it a try.

Sure enough! I desoldered my 245's and popped them back in a strange configuration to match the 244 pinout, and instant working filter was achieved. Sounds very nice! Thanks for giving it a look and a suggestion!

Hi all, I have a Befaco BF-22 filter that has been flummoxing me for some time. Today I went over the components with a fine toothed comb and found a single variance from the BOM: I have a pair of BF245C amps rather than BF244C's, which is what is in the BOM. I pulled up data sheets for each and see...

The new J111 arrived and has been successfully installed. The LFO reset now works like a champ and the module is complete! I even calibrated it last night, so its ready for some knobs and to be called 'done.' Thanks again everyone for your help in troubleshooting this one!

I have a Befaco A*B+C v2 that is working well on on one half but the other half needs some help. The lower half of the module seems to only put out about a 1V range as I adjust the C2 Level pot, while the top half seems to have a range of about 10V, going from -5V to +5V. The LED on the lower half j...

lol, thanks! It figures that I had the wrong docs. I had noticed that two resistors' positions on the board had been swapped but didn't think anything of it. A new J111 has been ordered and I'll know what to do with it when it arrives.

Many thanks again!

Hi all, thanks again very much for the help! I took another pic of Q10 that shows the silkscreen and the transistor: https://dansteeby.com/wp-content/uploads/q10.png I'm PRETTY sure this is backwards, but I did remove it and sure enough, the LFO started working. I unfortunately also snapped off the ...

X1, X2, X3 and X4 are headers and it looks like X1 mates with X3, and X2 with X4. So when the boards are mated together, X1-8 is joined to X3-8 and so on. The voltages you've measured look sort of ok: IC4B is the comparator and that has gone full negative as it should. This should make the integrat...

Ok, let me try to approach this another way. I'm trying to follow the schematics of this module as provided in the build document (link in my 1st post). I'm confused as to the labelling of points on the schematic. The LFO circuit is at the bottom of the 1st page of schematics, but there are extra sc...

I've built a Fonitronic PS3100 and the 3 resonators are working great. :sb: However there is an LFO on the module that is not LFO-ing. :goo: It is outputting a steady 0.64V at its output jack and does not seem to be affecting the resonators in any way. I've located the IC in question based on the sc...

guest wrote: ↑

Sat Aug 01, 2020 8:15 pm

its sort of looking like the microcontroller pin might be bad. do you measure 0v-3.57V on the micro pin as well?

I'm able to get a range between 0.97 and 5V on Pin 7 of the microcontroller as I adjust the offset pots. Many thanks again!

Hi all, thanks again for the feedback. I'm taking another stab at this now and will try my best to identify things by the schematic designations. I tried to trace the continuity from pin 7 of IC1 on the main board to pin 5 of IC3 on the expander board and found a trace that had been cut on the main ...

what are the voltages on pins5,6,7? you could try desoldering the 2 resistors that come from the output of the opamp, and check the opamp again. that will see if its getting loaded down by that part of the circuit. The voltages on the pins on the TL072 are: 5 0 6 0 - 1.5V as I adjust the offset pot...

Thanks again for the tips, I followed them and continued to poke around until I found a bad connection in my jumper ribbon cable that ran between the boards, which was the cause of the BIT 2 LED and jack not getting voltage. I replaced the ribbon with a fresh one, and have tested each of the cables ...

I've rewired my jacks on the main board and have moved on to the expander board. Things look promising there, as lights blink merrily as I twist the offset pots on the module, which is promising! Except for the Bit 2 LED, which never lights up. :goo: I can trace a good connection from the expansion ...

it has to be something with the wiring or jack, as the +/-5 is derived directly from the 0/5, so the 0/5 must be working at the opamp. probe the opamp output, wire solder joint on either side, jack tip connector, etc. After much prodding and headscratching, I've realized that the module in the buil...

Thanks for confirming the ground lug! I've soldered a wire between each of them and found the unused 'ground' pad on the PCB and have connected everything together. I'm now able to see the OFFSET pots adjusting the output of the ±5V output, but the 0-5V output is still not showing anything coming ou...

Great to hear re: voltages so far! Which of the lugs on the panel-mounted jacks is the 'ground' lug? I'm guessing it is the the "top-most" one, but figured I should ask to save myself some potential desoldering in the near future. Here is an image of the jacks I'm using: https://modularaddict.com/me...

Many thanks again all for the input! I think I've finally fixed the images. Suggestion to OP- Upper and Lower TL074 in your voltage readings would be much better replaced with the part designators from the schematic. Sure, we can figure it out, but... Anyway, are you certain the PIC has been flashed...

Hi and thanks for the support as always! Pins 18 and 19 do jump back and forth beween 0 and 5V as I adjust the offset knobs, so that much looks promising. Likewise, the voltage on the expansion header pins are also jumping back and forth between 0 and 5V when I adjust the offset knobs. The 0-5V outp...

Hi all, I have a Barton Bytwise Operator + Expander that needs some troubleshooting. It is not putting anything out on the +5V output when I feed it voltages into the X IN and Y IN with the X and Y offsets set to various positions and the switches and buttons in various positions. This is a tricky o...

Excellent! As a self-builder of my own cases for this project, I applaud your progress!

I'm no pro with tolex yet, but it's not that hard to do with adequate spray glue and superglue for any stubborn corners.

I managed to hide most of my worst mistakes with corner brackets, etc.

Well after a long delay, I've finally put two cases together and started ordering parts for the modules. Finding the BOM a bit of a PITA as it isn't exactly specific regarding things that have to physically fit, i.e. pots and switches. Also having trouble finding knobs that look the part - can I as...

Hi all, does anyone know where 1/8" stereo to 1/8" mono "Y" cables can be obtained for use with Akai MPC One/Touch/X for the CV outputs? They are stereo outs that then need to be split into mono, and the only "Y" cables I've been able to find have 1/4" connectors on the mono end, which I would then ...