Final Verdict: The mainboard’s firmware storage is irrecoverably corrupted at a level below user or service tool repair capability.
If you have performed a full memory clear and a firmware recovery, yet the printer still displays an internal error before any job is sent, the main board is the likely failure. At that point, parts cost may exceed the value of the printer (refurbished SCX-4623F units sell for $80–120). Warning: This will erase network settings, fax phonebook,
The SCX4623F has a hidden service menu. You can attempt to bypass the corrupted data by forcing the printer to verify its engine first. Warning: This will erase network settings
Warning: This will erase network settings, fax phonebook, and custom presets. and custom presets.