The PB adapter I bought is a M5651. According to the chart at the link below, it might work on PB 100..

https://support.apple.com/kb/TA32393

While the section on the M5651 doesn't name the PB 100, the section for the APS-17adp states: "Warning: Using an AC adapter that produces more than 19 W with a PowerBook 100 or 150 computer will damage the computer's logic board." The M5651 is 19 W so it technically should work?