1978年以前生产的SBR—4包裹收寄机,由于原电路设计考虑欠周,致使两种故障在所难免,故障的现象是;1.在单双09时,指针千克触点处于整公斤骑缝处,重量指示误加150克。2.在某个双单百克时,指针百克触点处于整百克骑缝处,重量指示误加150克。这种由于计算继电器吸合时间节拍不协调造成的计算不准,在电路里很难从元件上找到 Before 1978, the production of SBR-4 parcel send and receive machine, due to the original circuit design considerations less weeks, resulting in two kinds of failures are inevitable, the phenomenon of failure; 1. Single and double 09:00, the pointer kg contacts in the whole kg riding Office, weight instructions plus 150 grams. 2. In a double one-hundred grams, the pointer Hundred grams of grams of contact at the junction of the knuckle, the weight indicator plus 150 grams. This calculation of the relay pull-in time due to the lack of coordination of the calculation is not accurate, in the circuit is difficult to find from the components