I place a record, press start, record plays for about 1-2 minutes, then tonearm cues and tonearm returns to beginning position (1st track) in cued position and platter stops. Any adjustments to correct this? or does this sound like service may be required. Does TT have to be precisely level, or is this not a critical issue.Also there is a white plastic screw recessed on the under-side back right of the cover with a -/+ notation for it. What is it? How do you adjust tracking force for the p-mount cartridge. This Technics was given to me by a friend w/o a manual. Is there one available? Thanks for any info.