I found this on the web : i'm a tech and i'll tell you the secret. the moisture sensor is a little black square on the side of the drive motor. if you look directly where the tape goes in, the drive motor is in the far back left. it's partially hidden behind a silver pin hanging down from the black plastic cover that goes over the video head. take a long q-tip and dip it in glass cleaner(windex etc) and gently wipe it off. you should see a small amount of black guck on the q-tip. then remove power for about one minute and allow to dry. it's better to use air to dry it out.
Its difficult so I couldnt clean it good yet but for some people it has worked
Edwin Acevedo, January 2006