It is normal on an ARXA, so I wouldn't be too surprised. Something about the way the starting system (switch/ capacitor,etc.)is wired. Sorry, I'm no expert on the Phillips though.
Philips 437 turntable
I recently picked-up a Philips 437 turntable and I noticed when I was changing the belt that I could feel a little vibration in the motor shaft, (especially with the belt off) even with the switch in the OFF position. It doesn't feel like it's trying to spin, it just feels like there's power going to it. The turntable operates normally otherwise, It just seems unusual to me that there would be power going to the motor( all of the time ) and I wondered if someone else with a 437 would be willing lift the platter on theirs and see if it's normal or if ( more often the case for me ) mine has a problem. Thanks.