The Nonin pulse oximeter has a hinge like apparatus that holds the larger display portion and the smaller sensor portion together. If these two pieces come undone they can typically be put back together.
If all else fails, contact Vivify Support.
- Confirm the silver coil spring and brown data cable are still intact
- Hold each side in one hand
- Pull pieces gently apart in parallel until the two "teeth" near the hinge align and the pieces connect back together
- Release both pieces
- Take a reading and confirm the display turns on