last night, I just couldn't sleep so I decided to get my hands dirty and look at the sony ps-t1 I was planing to salvage for my current project and I understood/learned a lot of things, fisrt the motor isn't an ordinary dc servo but a hall effect dc servo, a motor that should be almost as precise a quartz controlled system but the electronic isn't stable enough because of the voltage regulator and the magnetic interference of the motor to the magnetic coated platter. but still the control unit is similar to a fg dc servo so I've been able to run some test to prove right or wrong what I thought. first I learned that I can trash one half of the circuit I had designed because of a mistake of interpretation in the design of the motor. second it confirmed what I thought about the bearing, it's a piece of s**t, you can't really lube it and the magnet is pushing on it. third, the only pieces that can be kept from the TT are screws, some pots, a switch and a point bearing. fourth, the pitch control is really bad, the strobe is controlled by the phase directly from the wall which is variable...
doesn't seem like the most interesting night but it was cool