Power-On Password - IBM PS/2 50 Hardware Maintenance Service

3.0 Power-On Password

To service a system with an active, unknown, power-on password do one of
the following, depending on which battery and speaker assembly is
installed.
On the type with two pins on the side of the speaker assembly, short
the pins together.
On the type with no pins, insert a meter lead into the connector
(protruding from under the battery) and short the other end of the
lead to frame ground.
Power-on the system and leave the assembly shorted until completion of
POST. This deactivates the password.
IBM PS/2 Model 50 HMS
Power-On Password
3.0 - 1