Heads Become Offset Causing E9 & E25 Errors

This FCO document outlines a mandatory update for RA70 disk drives manufactured before October 1991 to resolve a recurring issue where the positioner block stress relief causes head offset. This offset results in E9 and E25 errors and potential customer data loss. The solution requires replacing the UV ROM with a newer version (V83). The procedure involves accessing the Electronic Control Module (ECM) assembly, separating the servo and read-write modules using electrostatic discharge (ESD) safety measures, replacing the ROM chip in socket E4, and reassembling the unit. Post-replacement, the drive must undergo power-up, spin-up, and HSC/HOST diagnostics to ensure functionality.