Determining the ROM version of your SY99 

You can determine the ROM Version of your SY99 by pressing the following keystroke sequence: 

[VOICE]-[INTERNAL]-[1/OP1] 

The Main ROM and SEQ.ROM versions will appear on the LCD Display. Press [EXIT] to leave the ROM information display. To update your SY99 ROM, contact Yamaha for replacement. 

Please contribute your unlisted SY99 ROM versions (and date) to the FAQ maintainer 

Main ROM versions 

The following Main ROM versions are known (Year - Month - Day): 

Version 1.13 1991-05-28
Version 1.24 1991-07-09
Version 1.33 1991-08-21
Version 1.40 1991-09-25
Version 1.57 1992-05-12 


SEQ. ROM versions 

The following SEQ. ROM versions are known (Year - Month - Day): 

Version 1.10 1991-05-22
Version 1.20 1991-06-22
Version 1.30