In the 1980s planning for a major maintenance and modernization program began. The largest modifications were the electrical system in the turrets and the gun periscope. New periscopes were ordered from Yugoslavia, but the break-up of the nation and the resulting Yugoslav wars caused delays. The guns were equipped with gun computers and laser range-finders, and some of the turrets also with night-vision systems. The electrical systems were replaced using western components and the guns and gun positions were overhauled. Externally the most visible change was new thermal insulation dome on top the turrets that also gives them a more rock-like appearance for camouflage.