Struggling to set my tonearm height correctly and get it parallel to the pickup sensor arm. The service manual says to adjust the tonearm using screw B, but I can only get it to a state where I can adjust the maximum height (and get it level with the pickup arm) but it always flops down. To put that in context, I’m lifting the tonearm up and adjusting the height so that it’s level with the pickup arm. Releasing the tonearm it drops down. Im not sure whether I do this with power on, cartridge in, record in place etc etc the manual isn’t very helpful. Similarly, getting the tonearm parallel to the pickup arm using screw C is impossible. Screw C seems to be made of plastic and a bit on the fragile side. The tonearm waggles about all over the place, so trying to get it parallel needs me to start in a steady state, which I don’t have. On a final note, how do I clean the arms - they’re a bit tarnished. Thanks ! Jonny