I'm a bit more patient than most, but I would wait till Monday evening to 'push' this further. It is way to early to assume you got scammed. I'm not saying for sure you have not been, but you've not told me anything in your post that says you have been.
For arguments sake lets say this: he got the check monday, but probably did not deposit it till tuesday. The three day hold on the check is a problem caused by you because you did not pay with paypal, but the check. The fact that a bank places a hold on a check may not make much sense to you, but you must remember it takes time for the check to make it's way from his bank to your bank and it takes time for your bank to wire the money to his bank. The money is not actually 'his' till that happens. To be sure, Paypal has it's own issues, but as a buyer (not necessarily a seller) it is a great thing. Anyway, three days from Tuesday is Friday, maybe even Saturday since deposits done after 12 noon at many banks are sometimes are not credited till the next day which would have been Wednesday, three days from is Saturday. Today.
Could the seller be more communicative, absolutely. Could you be a bit more patient, absolutely . I do hope this works out for you. The Boss unit is a great one . I used one for quite a while.