They have a buy 5, get 6 pricing on the voice modules. I still do some acetone strips but prefer folks to order the complete package of 6 voice and 3 wave modules from Analog Renaissance in Belgium ( Analogue Renaissance voice and wave module package ) and bring/send them with the synth.
This coating is much softer than epoxy so the epoxy is not applying any leverage on the chips. I also see failures of the Wave modules but the acetone strip (if the epoxy comes off with this method) does not seem to help as there is a red coating of “other stuff” over the actual chips that I have not tried to remove so cannot re-flow the soldering. This will not cure a bad chip but has recovered a far greater percentage of modules with far less fallout. I re-flow the solder on all the pins on my re-work solder station under a microscope, then coat the module with silicone conformal coating to seal the moisture out and protect them. This leads to the belief that it is not the epoxy becoming conductive, but more it is the that the epoxy was pushing against the chips and as the temperature fluctuates, it expands and contracts which eventually lifts legs off the pads on the PCB. Looking at these with a microscope I saw incomplete material removal between the pins of the chips, and pins on the chips and the chips pins going cold-soldered. Long term the acetone strip method was not holding up and I had a couple of units in for rework that had been to the xxxxSpa. A common belief is that it is the epoxy coating becoming conductive over the years that is causing the failures (dead, crackling, failing the various tests in Test Mode) and that the acetone strip method was a cure. If you have the original 80017 modules then you need to change them as a set as Roland warns your in the Service Notes that the timbre is different on the “a” variant. If the module has not failed the chances are it will so I recommend changing all 6 80017a modules. We all know about the voice module issues on the Juno-106. I just want folks to know what they are getting into up front and that it is not a quick and cheap fix as if the voice modules have not been dealt with then they need to be. If it is in physically nice condition and you want to keep it then it is worth investing in as it is a nice sounding synth. When quoting restoration/repair of the Juno-106 I often describe it as a money pit because of the amount of work it requires, and high parts price.