Hi:

The PSR 3000 use the PA300 power adaptor, I suggest if you do not want to damage your keyboards, to use ONLY the manufacturers adaptor, sometimes to save a few dollars, may cost you a lot in repairs.
I see in the lower end of the boards there are "generic" adaptor, Mutec to be precise, for the Casios and low price Yamaha's.
There is not a "generic" adaptor's brand for the PSR 3000 that I know, I had a customer that literally fried his keyboard.