Place large capacitors on the back of the PCB (yellow). MAKE SURE ORIENTATION IS CORRECT.
Do not install items crossed-off in red.
Component value changes are in red.
Cut trace on rear-bottom of PCB.
Make note of the jumpers (orange), and while soldering components use the appropriate leg as a jumper (see diagram below).
Click of the pictures below for more detail.
Install components as usual: Resistors, diodes, capacitors, sockets, headers. Do not install ICs yet.Pots, jacks and the switch can be installed accurately with help from the front panel. Install the parts on the PCB, then place the panel over the parts to align and then hold in place while soldering.
The MIDI connector is mounted to the front panel and soldered to the PCB. The benefit that there is no stress to the PCB when plugging in the cable. The drawback is that it will need to be unsoldered to remove the panel for access to the top of PCB — so make sure everything is working before soldering the MIDI connector.Cut the two outer pins and the middle pin as close to the base as possible. Bend the remaining three pins vertical so they fit into the PCB.Attach the MIDI connector to the panel, making sure the orientation is correct. M3x6 panhead machine bolts work great.DO NOT solder the MIDI connector to the board yet.
Before installing the Arduino Nano, check that the power lines aren’t shorted with each other, then connect the Eurorack power cable and check the board for 12V and -12V. It’s okay if they’re off a couple volts since there’s not much of a load.Program the Arduino Nano with the IDE and the code. You will need the DigitalWriteFast and MIDI libraries. Here’s instructions for installing drivers if you need it. Make sure that you have “Arduino Nano” selected as the board in the IDE.With the power off, install the Nano, making sure that it’s oriented properly. Apply power while watching the Nano. It should blink at it boots up. If not, shut off power and check for shorts.Check the 5V and 3.3V test points. If these are okay, disconnect power and install the 4051s, opamp, and dsp-G1 — double check orientation!Power-up the PCB while looking at the Nano. If the Nano doesn’t blink immediately disconnect the power and check for shorts.If the Nano boots okay, connect the MIDI (loosely attach front panel) or CV/GATE and test all functions. The MIDI connector should make a solid connection to the PCB without soldering.If everything is okay, attach and tighten the control nuts, then solder the MIDI connector.DONE!