American Weigh Scales AT-500 - Manual (Page 4)

V. TROUBLESHOOTING
The primary reasons for inaccuracy or malfunction
are low batteries, incorrect calibration, overload or
operating on an unstable surface. Please keep this in
mind and maintain and operate your scale properly.
This scale is a precise instrument and must be
handled with the utmost care and caution.
[Display] Elimination of errors
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[Err] You are overloading the scale. Remove the
excessive load immediately!
[UNST] Use the scale in a more stable position