Welcome.
Has the KR 4500 got a seperate power supply or is it built into the keyboard.
If it is seperate then it could be worthwhile testing the output terminals to see if there is a voltage present. If there is no voltage then there is a fault with the external power supply.
As for the stand, the answer is probably not, but you can always take the keyboard off the stand, measure up the mounting holes and comparing them to new Roland DP stands.
I am unsure if the pedal connection will be compatible with new DP's
If you do go the new DP route you could always make up a timber top for the stand and connect them up using the new timber top as an adapter.