I would try it without batteries-- at home, of course, before you get into a gigging situation-- to see what happens, so you'll know the definitive answer to the mystery. The newer PSR models retain the Registrations and other backup settings whether or not there are batteries in them or their power adapters are plugged in, but I'm not sure about older models such as the PSR-350.
As far as keeping batteries in the keyboard while also using the power adapter, I don't think that's a good idea, as I seem to recall reading that you shouldn't do it-- probably something to do with how much power is being fed to the keyboard's electronics. If you do find that the settings are getting lost unless the power adapter is plugged in or there are batteries in the keyboard, then it would probably be best to remove the batteries whenever the power adapter is plugged in and the keyboard is turned on.
Also, it isn't a good idea to leave batteries in the keyboard while it isn't being used-- at least not for extended periods of time-- because if the batteries corrode it can damage the connections inside the keyboard. For that reason, I'd be surprised if the keyboard were designed to lose its backup settings whenever the batteries are removed, although the wording of the manual does seem to imply that such is the case.
I would try it without batteries-- at home, of course, before you get into a gigging situation-- to see what happens, so you'll know the definitive answer to the mystery. The newer PSR models retain the Registrations and other backup settings whether or not there are batteries in them or their power adapters are plugged in, but I'm not sure about older models such as the PSR-350.
As far as keeping batteries in the keyboard while also using the power adapter, I don't think that's a good idea, as I seem to recall reading that you shouldn't do it-- probably something to do with how much power is being fed to the keyboard's electronics. If you do find that the settings are getting lost unless the power adapter is plugged in or there are batteries in the keyboard, then it would probably be best to remove the batteries whenever the power adapter is plugged in and the keyboard is turned on.
Also, it isn't a good idea to leave batteries in the keyboard while it isn't being used-- at least not for extended periods of time-- because if the batteries corrode it can damage the connections inside the keyboard. For that reason, I'd be surprised if the keyboard were designed to lose its backup settings whenever the batteries are removed, although the wording of the manual does seem to imply that such is the case.
Mike,,,,, GUESS WHAT THE ANSWER IS ,,,,,,
After perusing your comments,,,,, I put batteries in, and MEMORY RETAINED !
Tried with AC power and batteries in, and MEMORY RETAINED !
After reading your comments about batteries,, plus,, power,,,,,,,,
I REMOVED the batteries, and VOILA,,,,,, MEMORY RETAINED !
Turned Keyboard OFF and removed the Power,,,, then after awhile I plugged it in again, turned the Keyboard BACK ON and ,,,,,, TO MY AMAZEMENT,,,,,,,,,,,,,,,,,,,,MEMORY STILL RETAINED !
Conclusion: DONT BELIEVE EVERYTHING IN MANUALS ! !
Mike, NOW we both know the answer ! ..... THANKS AGAIN.