Not sure what the problem is, but it may be a missing or messed up belt.
Possibly the electronic mechanism that tells the arm to lift is defective.
I had a DP EC7, which I gave to my nephew, had a similar problem.
The arm would lift before the record was finished.
The problem was a defective mechanism, needs to be adjusted, but not done yet.
Look inside the unit, and see if you could figure out the mechanism.
The schematic may be available on Vinyl Engine, check it out.
Cheers