So every once in a while I jump into figuring something out that I’ve never done before. I’ve taught myself leather-working, reverse engineered slippers and soldered a 40-year-old circular saw back to functioning - all in the past 6 months.
This is a photo of the direct drive turntable with all it’s direct-drive glory revealed. It’s technically an induction motor which utilizes a stator to create an electromagnetic field which pushes and pulls (rotates) the platter (that the vinyl lies on). I had run across an induction motor in the old casted Craftsman circular saw I had reverse engineered a few weeks ago - really amazing and self-contained mechanisms. This type of motor revolutionized industry and how we use electricity. If a device is DC - and it’s bigger than your hand - it’s probably got an induction motor in it.
I wanted to fix the table as it was spinning out of control. Sometimes it would go 33.5 rpms, then speed up like crazy where I thought it would damage the needle. There weren’t any apparent variables to indicate the source of the problem. As in: if I hit this switch or unplug the audio cables from the amplifier, it wouldn’t effect how the table played. Or, if I left it on, spinning really fast (assuming components are heating up) it may or may not drop back to 33.5 rpms. Sometimes I would hit the base of table and then it would speed up then shut it off and turn it back on again and it would return to 33.5 rpms a few minutes later.