Hello, I had recently tightened the tonearm of my SL 1200 MK2, which basically required me to unscrew everything on the bottom, including the pitch slider, tonearm base/tonearm setup etc. from the bottom. When I put everything back together, and I played a record, occasionally the speed would jump incredibly high, and the green light would dim a bit. The calibration on the pitch slider was so bad that if I wasn't on the 33 RPM center by just a hair then the speed would jump.
My hypothesis for why this would be happening is this: I think for whatever reason I occasionally have the pitch slider in the middle, but not quite in the middle enough so it'll actually go out of the "green light middle" a little bit, and since it's calibrated so badly that means that it jumps in speed when this happens. But it could be something else.
Admittedly this hasn't happened in a while, but I really wanted to know how to prevent this. Another thing to note is that it happens usually after I fool around with the pitch slider, leading me to believe further into my theory on the second paragraph.