Build an interface to the serial EEPROM … not too hard, but plenty of points of failure!
You must construct the circuit as shown on the Normsweb page using specified resistors, Zener diodes, and the female serial connector.
Use a USB-to-Serial adapter to link the ThinkPad to another PC using a 5V connection. Even if the second PC has a dedicated serial port, that port will run at 9V, potentially causing an over-voltage condition on the EEPROM chip. These adapters are found on the cheap through eBay, and the one which I bought worked instantly thanks to Windows 10’s automatic driver installation.
Simple fix: in case you happen to purchase a ThinkPad from the same organization as me, the password was “DOGLOVE”. It’s worth a shot, I guess!
This link illustrates how to read an EEPROM using an Arduino device instead of the standard PC serial connection used elsewhere. I didn’t try it, since I don’t own an Arduino, but it looks promising.