by Rob-NYC »
Wed Dec 30, 2015 2:51 pm
Unfortunately, those noises are typical of an aging LPC, but here are some things to check;
1) Lube the mech properly and thoroughly w/20wt non-detergent oil. Remove the top bearing over the motor worm and oil that extra well. There is an oil hole in the thrust bearing nut, but old oil and glaze can displace new oil and make lubing that beaing difficult.
2) Check for a supple motor coupling. Replacements are available.
3) Check that the motor mounts are still rubbery but not allowing the motor to shift when reversing. Be sure that there is a rubber plug support under the bottom center of the motor.
Understand that the motor is getting approx 83 Hz when playing a 45 and this does raise the frequency of the vibrations from the motor and can induce mechanical harmonics.
In case you are wondering why Seeburg used a native 33rpm mech, it was because 33's had inherently lower output causing the amp's AGC to turn up the gain. Since the motor was going to make more noise when powered by the less-than-perfect sine from the speed unit, it was felt that the louder 45 would better cover that noise. This was explained myself and a friend by a rep from Seeburg in 1977 and it does make sense.
BTW: You mention the memory as being "electromechanical" -it isn't. It is an early form of NVRAM -all electronic. The toroids can retain their state essentially forever unless flipped.
In 1998, I rebuilt a Seeburg K that had been retired in 1961 and stored till I bought it. After complete washing and rebuilding I powered it w/mech connected and it detented at about 7 slots that must have been selected eons ago.
Rob
"If we believe absurdities, we shall commit atrocities" -- Voltaire