Roland Synth Repairs

Juno 106

We get a lot of these, Roland made loads of them and they were reasonably priced. This was the updated MIDI version of the Juno 60, with software envelopes and LFO and the addition of Portamento.

The most common problem with the 106 is the “dying voice module” syndrome. The filter and ouput VCA are built onto a ceramic circuit board as a vertically fitted module called the 80017A. The 106 has 6 of them.

The symptoms vary depending on what part of the module has failed, but voices stuck on and strange resonance behaviour are among the most common. Replacement modules are available from several sources but needless to say are expensive.

Other fairly commonly found problems are faulty switches, broken or worn out sliders and broken pitch benders. All of these are available as new cloned parts from the far east.

The 106 is a great sounding synth, it’s MIDI spec is very good for the time, and its value has been steadily climbing for the last few years. Many of the 106’s we get are from abroad but most can be readily converted to EU or Semko standards to work with standard IEC mains leads at 230VAC.

juno-106-voice-module-80017a-removedJuno 106 Voice Board and the famous dead voice module


There are a lot of these in Ireland, we see them regularly. Due to the external Wall-Wart many of these have damaged internal power supplies due to incorrect external power supplies. Badly corroded battery terminals are also quite common (even alkalines will corrode eventually).

The most common serious problem is the demise of the Curtis CEM3340 oscillator chip, the symptoms are obvious, the synth makes no sound apart from the noise generator. The CEM3340 is becoming a rarer and rarer chip these days, as so many synths worldwide used it and it has been out of production since the mid 80’s. Expect to pay €50 these days just to get hold of one of these chips.

Other issues are worn out sliders and dodgy keyboard contacts.

Despite the above, the SH101 is a very reliable synth, it is well built, sounds very good and the far east yet again can supply a lot of the otherwise unobtainable spares.


An SH101 on the workbench

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