Are you sure you didn’t have something else going on? Why the heck would Atari release a computer their own disk drives wouldn’t work with?
+5 READY line is not used for power if that is what
is behind the thinking there, it's only purpose
is to tell devices on the SIO chain that the computer
has power and is READY.
My real drive with R63 intact would not work, so I
jumped it and then it did work. Only thing I did too.
Besides, R63 is a current LIMITING resistor. It doesn’t disconnect the signal entirely.