The ammeter is a pretty simple animal. There are no windings or other components to go bad. They either work or are broken and then you have no power in the dash. Yours looks to be hooked up an working. As long as the needle "zeros out" with the key off, there is no adjustment to make. The only other problem you have with them is loose wire connections on the posts. If the insulators compress over the years, the nuts can loosen a bit and the power can arc from wire to post. If the insulators go bad completely, the wires can short to the housing and melt your harness. Just make sure the insulators are good and the nuts are tight and you should be good.