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

Thanks,
Jon Lloyd
jglloyd@pdq.net

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Photo credits: Stefan.Haselmeier@netsurf.de