A Peek Under The Hood.
The main circuit board in the FS1r is small, about 8 inches square. It appears that Yamaha made the main board so it could fit in either a full size rack or a half rack. This is the way they designed the MU100 and MU100r.
Here are the components on the main board:
1 Hitachi Super H8 microcontroller 6437044E07F Yamaha part XV10010, 112 pin QFP
1 Mask ROM (512K or 1MB by 16), MX chip (no MX part number) Yamaha part XT52410, 42-pin DIP
1 Mitsubishi M5151008BFP-70LL 128KB x 8 Static RAM (Battery Backed) (128K bytes of RAM is used for user data and system settings)
1 Dynamic RAM chip, OKI M514260-60TK, 256K x 16, (used by H8)
2 Yamaha YSS236-F ASICs (160 pin QFP)
2 Yamaha YMP706-F ASICs (128 pin QFP)
1 Dynamic RAM chip, OKI M514260-60TK, 256K x 16, (used by YSS236 DSP)
2 Sanyo LC78834M Stero 18-bit DACs
1 CR2032 3V battery (removable)
7 JRC 4570 op amps
1 JRC 4558 op amp (drives headphone outputs)
13 misc glue logic chips
Click image for bigger picture.
Photo credits: Stefan.Haselmeier@netsurf.de