Originally Posted by
YorkshireDave
This might not be the problem you have, but it's worth mentioning. Make sure your cellphone (and anything else which transmits eg wifi, bluetooth) is well away from the scales. A few years ago I was weighing titanium fasteners for a project and I noticed that the scales often read wrong when there was a cellphone within 8-10' of them. Not far enough wrong to be an obvious rogue reading but far enough wrong to screw up the results. Tried 4 sets of scales, got exactly the same type of errors on everything from a £25 pocket scale to a £1500 pharmacist's lab balance, the only difference was that the pharmacist's balance needed the phone within about 2-3' before the problem started.