Home Scale Question

hey guys so i got this old ac machine from my dad it was long past working and even had been striped down for most of its useful parts but one thing it did have in it was a scale a 100lb scale for that matter i know nothing about scales so i decided to open up my cheap 15 dollar Walmart scale if nothing else to learn more of how they work well ended up being able to wire this thing right up after a few min of tinkering im getting a read out of 1 pound per 10 pounds on the scale (the walmart scale was a 5lb scale)

my question is how would i go about getting the proper curcit board for a 100lb scale so i get the correct read out is there like replacement parts for this stuff? ive searched around some but i cant find much feels like i maybe wording what im looking for wrong any help would be appreciated.