1. How to adjust counterweight and balance the tone arm?
You can watch the quick installation video via this link:
https://www.youtube.com/watch?v=3QttL2lbUx0
2. Can I purchase the replacement power adapter of this model?
Yes you can purchase the replacement power adapter from mbeat.
3. Where is the counterweight located inside the box?
The counterweight (with Black dial) usually is placed at the side of the foam inside the box. Please check carefully.