The socket memory is empty; in the same page of the manual it clearly states that you can fill it with either a 512 or a 1024 Mb module.
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Korg Kronos 61 and PA3X-Pro76, Roland G-70, BK7-m and Integra 7, Casio PX-5S, Fender Stratocaster with Fralin pickups, Fender Stratocaster with Kinman pickups, vintage Gibson SG standard.