Welcome to VE......
I noticed that service manuals were recently added to the VE library.....
If your unit is CAN, then download the "M / MC" service manual.
The sister / predecessor turntable is the SL-6, you can download the instruction manual here. Operation is still the same, just 2 less programming buttons....
From the 6 Operating Instructions the unit is looking for an LP on the platter, it's not detecting one and returning to the start position. Except the cueing soleniod is not holding the tonearm up as the LED eye is scanning the surface.
Initial guess is that the detection LED sensors are dirty, non functioning and the tonearm plunger circuit needs some TLC.
With a 12" LP loaded on the platter, what happens if you just push the cue button ? On my Technics linears the tonearm will move over to the first band of the LP and begin playing.
What happens of you push the "1" programming button, will it start to play the first band ? Will the turntable start scan and to play any of the bands directly ?
If you do see that the tonearm drops / hear the tonearm solenoid initiate causing the tonearm to drag the needle across the grooves, you can always lift the dust cover which takes the tonearm up off of the record and prevent the needle from physically dragging and damaging the stylus. If you do perform this physical up dustcover abort, the tonearm should then cue up and move to right to it's rest position.
Anyway for starters, I'd try and clean all LED sensors first. Then study / troubleshoot the cueing control circuit.
Read through this topic as it may aid in troubleshooting. Technics tangentials are all similar in operation and logic. While you've got things open, you can check out the condition of the lube and tonearm drive belt.viewtopic.php?f=16&t=23432