With the refurbished voice chips installed , and the original factory presets loaded in, I was really enjoying playing my Juno-106. I even decided to use it as the primary source in a synth-pop cover of Pink Floyd’s “Comfortably Numb.” But something kept nagging at me. What if it overheats? What if it just dies? What if all my work and expense is for naught? It was time to open her back up and do a little more work before continuing with the music. Of course, there’s a lot more work to be done—greasing the sliders, changing the tact switches, brightening the buttons—but none of that will mean anything if the power transistors fail. There’s a big heat sink connected to the power supply board, with a number of transistors bolted to it. I’m no electronics expert, so my knowledge here is limited to what I’ve gleaned from the internet, but it seems like these transistors are pretty important. Because of long use, the solder joints connecting these transistors to the PCB can devel...