You stole it for what you paid
Go to vinylengine and download the service manual.
You will need to replace a belt which drives the tonearm, replace some old dried up lubricant, and possibly a turntable drive belt (not sure if this is a direct or belt drive model)
For the ground wire, I just thread one though the hole for the proprietary technics cable and screw it to some metal inside the unit. You may prefer to order a cable, I believe they're about $10 online.
Get a replacement stylus too.
As for sound, etc? I love the full auto linear trackers of the 80s. I have a technics SL3 as my workbench turntable for testing amps, and I also have a Sansui P-L95R which goes one step farther and plays both sides. They're a bit fiddly to get into top working order but the reward is a trouble free and relaxing experience.. all manual works for some people but I like automatic players since I listen late at night and often fall asleep with the music on.
Linear trackers get rid of the inner groove tracking distortion which plagues cheap record players. Cheap ones dont sound we nice as expensive ones but this should come as no surprise
anyhow good luck!