This issue pertains to the original Force Plate (FP-BTA), shown here. Newer Force Plates, shipped after November 10, 2023, do not have this issue.
Which force plate do I have?
The issue is caused by metal pins in the load cells falling out, which can happen during shipping. An additional symptom may be that if you squeeze the top and bottom of the force plate together at one corner with your fingers, the top surface of the force plate will tip toward the corner you are squeezing. Tilting the force plate and turning it upside down and back may result in pins falling out of the housing.
Force plates with this problem will not read correctly and cannot be calibrated to read correctly.
If you have a force plate with this issue, contact Vernier technical support for assistance at physics@vernier.com or 888-837-6437.