I had this error, finally fixed it.
First i took it apart and put it back together - but I suspect this wasn’t neccessary.[br]
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YOU CAN FORCE IT INTO CALIBRATION MODE!
# power on
# immediatly press and hold the “Tare” button until it shows you a long number.
# press mode once and it will show “CAL” on the display
# press mode once more and it’ll flash 100g
# Place 100g on the pad
If you numbers are jumping all over the place and it claims it’s Unstable after this, take it apart and put it back together. The trick to acheiving stability seemed to be tightening the screws holding it down just enough. not too much and not too little. ensure the load cell only connects with the tray at the one screw position.
The load cell works by analysing the stress accross the load cell (it’s the big bar that gets the pad secured to it.
Good luck - but honestly fixing this was probably quicker than taking it to the shop and coming back. and more interesting.