After a prolonged period of inactivity, a paper jam occurred in the fuser unit, causing it to fail. It was replaced with a new part. Upon restarting, the printer now reports that non-genuine toner cartridges are installed—which is incorrect (original okis onboard). All toner cartridges were replaced (this time with generic ones), yet the error messages persist. In maintenance mode (Level 1, Engine Diag Mode 00.04.09 f-mode), the printer reports the following under the "fuse intact" menu item: belt unit blown, IO unit blown, and fuse unit blown. What do these error messages mean, and how can they be resolved? The printer does produce a test print, but it contains no page content (blank sheet).