Roland MKS-20 -1987

User Manual: MKS page
Reset Proceedures: N/A
Operating System code:
MIDI or other control protocol: See Manual
Software related Links:
Patches or knob settings:
Circuit Overview: below
Scematics/Service Manual: Soon! meanwhile Manual Manor
Common Service Issues/Tips: below
Parts Sources: knobs semiconductors misc
Uncommon chips/modules used: Many
General Info Links: MKS page

Circuit Overview:
     A digital instrument. Here is an excerpt from the AH group by Gordon Reid:
The sound generation for the 'SAS' (structured adaptive synthesis) pianos was developed on a computer at Roland Japan called SALLY. In short, Roland sampled a range of pianos and reduced the sounds to a set of algorithms that related harmonic content to velocity. The sound regeneration system in the MKS20 and its peers uses these algorithms to reconstruct the correct timbre every time that you play THIS note with THAT velocity. It is, therefore, (perhaps) the first physical modelling synthesiser, albeit for just percussive keyboard sounds. Furthermore, by having 128 genuine, discrete velocity timbres, it is still far superior to most systems using velocity cross-fades between a handful of samples."
     Thanks Gordon. I'd rephrase that though to 'first acoustic modelling..'. The DX and related units modelled FM which is..after all a physical phenomena :-). The K5 K150 and so on.

Service Tips:
      I worked one over solder wise and got it up once. Reseat all chips and that sort of thing. If you get distorted output, it's usually a relay that gets dirty. There's a relay that gets dirty in there. Find the relay in the middle somewhere of the board as I recall though I might be wrong on that....but anyway there's only one relay I think...carefully remove the top (usually by whacking off one of the plastic sections near the bottom so that you don't have to hold two of them out at once..) and then spray deoxit on the contacts and work them a bunch or use very fine abrasive between them if necessary.

Roland might still have some parts for these so always check there first. Let me know if you need a specific part from my listings in the parts section that you don't find elsewhere or whatever.
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