These are the original Yamaha FM synthesis effort, packaged in a piano type case for the GS-1. GS-2 is more like a CP25 portable piano case. Carefully voiced 4 operator FM is the description I've heard. I think More of a museum piece now because of size and relatively crude hardware of course. Nice feeling keyboard of course and some classic sounds. Some site apparently had schemos up at one time. No more though that I can find. I read in a GS-2 ad that this thing had magnetic memory strips for patch storage and 16 memory locations. 2 AA batteries for backup. Hence they come up missing the sounds and there's no programming interface!
Synthark is doing an extensive job delving into these machines and replacing the typically broken readers.
While Yamaha normally does not keep parts around more than 5 years or so, I stock what I can.
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