hifi engine

Kenwood KS-4000R service manual and part source

I'm looking for the service manual and a place to find a replacement volume pot on a budget. (Post snapped off) Owner would like it fixed but so far only place online I found it is Germany for almost $50.00.
Are there any other places that might have it? When I was little I remember my dad taking me to Wise Electronics in Port Chester NY. Are there any places like that anymore?