The Roland Juno 106 is a well know, widely produced synth capable of a wide variety of great sounds. One unfortunate part of the construction of the 106 model in particular is that the VCA chips are coated with a resin that breaks down over the course of decades and causes short circuits. The remedy is to desolder the chips, soak them in acetone and tediously remove the resin. It's a time consuming process that does not always fix chips that can be too far gone. This picture shows 6 clean chips reinstalled.