Hardware methods are extremely risky. The FX3U has no soldered-in battery (like older FX2N), so removing power does not erase the password. To reset via hardware:
Mitsubishi Electric does not provide backdoor passwords for obvious security reasons. They will only assist if you are the legal owner and can provide a notarized affidavit, purchase receipts, and a valid reason. Even then, they will likely ask to return the PLC to a service center for a factory reset (which erases the program). fx3u password unlock
You cannot see the ladder logic, modify timers, or change variables. However, the PLC will still run the existing program. Hardware methods are extremely risky
Back up your project files ( .gxw , .gpw ) to a network drive. A backup eliminates the need to read the PLC at all. They will only assist if you are the