Yup, I recently recapped two PowerBook 230 Duos which both of them had major capacitor leakage. One of them sadly decided to quit working shortly afterwards, I believe that it was probably because of capacitor leakage.

You can quickly check for the leakage by simply lifting the keyboard. If the small SMD cap on the left side is leaking, then you know that the others are on their way.

Below I provided a quick diagram of affected capacitors. One of them is already removed.