Here are schematics for the Yamaha FX/FS series of organs. I’m scanning in what I have which are the schematics for the FX-3 and additional content for the FS-300/500.
These schematics are applicable to:
- FX-3
- FS-300
- FS-500
- FS-70
- FS-50
If you have a different model than listed above this will still be useful because most of the organs in this series use the same components–just more of less of them.
For example, the main difference between an FX-3 and an FS-500 is in the MEP board, lack of onboard speakers and amps, and differences in the power supply. Otherwise, the digital side and majority of the analog side are the same. The FS-300/50 is basically the same as the FS-500/70 minus the solo keyboard and the 50 doesn’t have lighting.
The FX-1 is largely the same as well, but it does have a different keying system and some changes in the couplers and other places. But I believe the digital side is largely the same.
These are pretty time-consuming to scan and edit, so I will add them as time permits.