Hi David,
I looked at the specs of the PSR3000 and quite frankly, except if you want to play more piano music, I don’t think the DGX650 would be a wise move if you liked your PSR3000.
Granted, the DGX650 has 88 weighted keys, some cool sounds (the Natural! piano, taken from the higher-end Clavinova’s, is really nice) and decent speakers, but it has only a 6 tracks sequencer with no step sequencing, no onboard style editor, no organ flutes. The styles have only one Intro, one Ending and two Variations.
I think that a nice replacement for your PSR3000 would be the PSR S775 or, if budget is an issue, the PSR S670.
That said, if you really fell for the DGX650 and want it, by all means try to get the DGX660 instead. It has more features such has the Piano Room, a mic input with effects, more polyphony etc.
I’d say go to the music store and try the PSR S670, the PSR S775 and the DGX660 on top of the DGX 650.
If this can help, there are plenty of demonstrations videos of all these keyboards on YouTube.
To sum things up, the DGX650/660 is a nice digital piano with limited arranger features so if you want a “real” arranger keyboard, go for the PSR S series instead.
What do you mean exactly by using your PSR3000 as a backup?
Hope this helps,
Vinciane