Service mode data is stored in a television chassis or set by duplicating all the data that is accessible by service mode, i.e. by storing the same data twice, in two separate areas of a single memory device or two separate memory devices. A “working memory” is always accessible by the chassis. A “reserved memory” is normally not accessible by the chassis. At the factory, the same service mode data is input to both the working memory and the reserved memory. The chassis microprocessor would normally only access the working memory. If any data in the working memory is changed (intentionally or not), the original factory data can be recovered from the reserved memory and copied to the working memory by executing a specific access operation.