Vintage PSW150 Subwoofer

hanker13

I recently acquired a vintage psw150 subwoofer that has two problems. I noticed that the pots for the volume and frequency need to be replaced. The knobs and posts are gone and I can't get anything into the posts to turn them. It looks like the previous owner tried to turn them with something and completely ruined what was left of the posts. Does anyone know where I can get new pots for the subwoofer? When I looked inside I saw that the Frequency pot is a Alpha B200k and the Volume pot is a Alpha 250K.

Thanks