The EA-1 balances with the electrical coarse tare had this tare adjusted so that one got at least 1,5 grams and the fine tare a total of 100 milligrams. The actual setting of the coarse tare knob was in such a position that one always got the 1,5 grams of plus tare. If on a particular balance, it was noted that the tolerances on the electronics gave much more than 1,5 grams of tare, the tare was noramally adjusted so that one always had at least 1,5 grams of tare on the plus side and the remainder was used for negative tare. The fine tare is adjusted at approximately the midpoint, so one gets approximately 50 milligrams of plus tare and 50 milligrams of minus tare. Consequently, on some models, the balance is zeroed with the coarse tare knob slightly away from the stop.
On the EA-1 balances with the mechanical tare, it is imperative that complete spiral tare spring freedom exists. All turns of the springs should be free from contact with other turns, the spring clamp parts of the mounting assembly, or loose parts of the wiring harness. This determination is necessary at zero tare and at full tare.
The clamping parts for the outer end of the springs should be tight and the spring end firmly held.
The set screw on the spiral shatf should be tight enough that there is no movement of the spiral spring during normal use of the balance. If this precaution is not taken, it could cause a lack of repeatability, zero shift, etc.