The drive motor is a large radio control airplane servo salvaged from my junk box that had the servo drive circuits removed. It is therefore just a DC motor that has a gear reduction output. On the servo output shaft is mounted a 1/32 slot car wheel with a foam tire. This slot car wheel is a drive puck that rides on the outside of the Plywood platter. The servo is pivoted on a spring loaded mount to keep tension on the drive wheel. This geared motor can move the turntable very precisely.
The indexing circuit board is stock but the photo resistor mount assemblies in the bridge are modified to provide better ambient light shielding with a hood and the light slot has been modified by drilling about a 1/16 in hole in it to slow the motor down as it approaches the indexing lamp.
Click on Schematic for larger view
One other gadget I added was a normally closed push button in series with the indexing pickup that if momentarily pushed will make the bridge to a 180 degree turn automatically.
I also added ball bearings to the bridge flanged wheels and a thrust bearing from a RC helicopter in the main bridge shaft to make the bridge run as friction free as possible.
I hope this gives you some Ideas to improve the operation of your turntable
Turntable Motor Controls. The push button does a 180 degree turn
Index and Track Power Control
Green - Clear Index LEDs. The common of the LED lead is soldered to the Turntable wall and the LED is aimed through a pinhole in the wall
