he's familiar with this particular ancient version of the st30. says spare parts are nearly non-existant, so be careful while you take a ball peen hammer and smash it apart. just kidding. pete says some judicious tapping and, if necessary, the application of lots of heat - like from a torch - will eventually get the top piece to start unscrewing. pb blaster is of little use because there is no easy way to get it to flow to where you need it to go.

thanks pete.