Thank you for the replies! I'll have to pull the amp and give it a look see for anything obvious.. Believe it was a power surge that got it. As I mentioned in the Sub forum, the red light comes on, but won't receive a signal from the Yamaha and no report/static/anything from the driver when plugging/unplugging cords and what not.
I do realize it's old and not of the best quality, but to a non audiophile, it's still a fine cabinet/piece of furniture and looks as good as the day I bought it. It still gets a weekly workout and does (did) quite well, with some old 70's-80's rock and roll.. Hate to just trash it. Thanks again and still open to suggestions for a plate amp replacement!
* I searched ebay for a used one but didn't see any KSW150's.. Is there a better marketplace to check? TIA