power supply question

[awright]

Do you meqn q music "keyboard" or a computer keyboard? I assume you mean a musical instrument.

Sounds to me like it is quite tolerant of power supply voltage variations. If it works, go ahead and use the 500 ma. PS, but either measure the current to be sure you are not exceeding its current limit or monitor its temperature (by finger) very carefully, especially on hot days.

If you see a circuit board it was probably originally a regulated supply, but not definitely. If the old PS is non-functional, open it up to see what's there and to see if it was regulated or if you can repair it.

Your interest is in whether the old PS was LIGHTER than normal, not heavier. If it is lighter than you would expect, it was probably an SMPS (Switch Mode Pwer Supply) and, thus, regulated.

Have fun.

awright