Harbor Freight - buy a new cheapo sander. Cut your old pads to fit.
OR- Find a auto-paint-body-shop supply store. They cater to all bodyshops, ask your local bodyman.
Buy common paper-backed discs of whatever grit desired. This ain't HomeDepot, so don't ask for 'medium'.
Buy a small amount of Disc-Adhesive. Maybe a tube, or can/w/brush.
Remove the hook pad from your sander. I used a blow-dryer. Zipped right away.
Paint on the adhesive, let dry, several coats, nice glossy surface.
Paint the disc with very-light-and-thin coat, let dry, slap on.
If you really want to be a pro, buy the pre-glued discs with peel-off wax-paper backing.
They don't smell like glue.
My 25yr old Black&D JitterBug, and my MonkeyWard orbital, are both converted.
The JitterBug cushions had hardened with age. I cut a old mouse-pad rubber, epoxy over the old pads.