To secure the top arm of the RØDE PSA1 microphone stand and prevent it from moving upwards automatically, follow the steps below:

1. adjusting the spring tension: Ensure that the spring tension of the arm is adjusted to suit the weight of your microphone. This can be achieved by adjusting the spring tension to hold the arm in the desired position.

2. secure attachment: Check that the arm is properly secured to your desk. Use either the Desk-Clamp or the Desk-Insert to secure the arm firmly and securely.

3. cable management: Ensure that the cables are properly managed to avoid any unwanted movement of the arm. The Velcro cable wraps supplied can help with this.

If the arm continues to move unintentionally despite these measures, it may be helpful to consult the instructions again or contact the manufacturer's customer service.