> Battery Notice: This product MAY contain a small non-rechargeable battery which (if applicable) is soldered in place. The average life span of this type of battery is approximately five years. When replacement becomes necessary, contact a qualified service representative to perform the replacement.
> Except for the data listed below, all PSR-550 panel settings are reset to their initial settings whenever the power is turned on. The data listed below are backed up - i.e. retained in memory - as long as an **AC adaptor is connected or a set of batteries is installed.**
I did see a forum post that talked about a "Gold cap" that basically held it's charge for much longer than the others and that was keeping the memory alive during power loss.