Well the moment you plug VGA cable into the monitor it gets ground signal and "knows" something is attached but that doesn't mean any part of that something is sending picture so that won't help diagnosing.
Since your floppy isn't clicking I "suspect" PSU , you can measure voltages with any multimer , just set it to 20 V setting and not on high voltage
Even better if you have spare PSU to try you might try that and before you do make sure that it's in "vanilla" state (same as it came from commodore).
Apart from that something might not be seated right.
P.S. Keylock behaviour was explained in this thread I think.
