I got this boombox from the painter of my house in the late 90's. It has been sitting inside a dirty closet for 20 years and more. It was in a rough shape and needed a bit of love when I got it, so I cleaned the exterior the best I could then went on to clean the interior. The tape deck need a new belt which is not surprising for a boombox from the early 80's but I also found this on the motherboard. I'm not sure what is it but I scratch a bit off and it's not completely hard. I know the boom box had overheating problems from the molten grills at the back of it but I don't know what's causing it. Would it be safe to use it once thoroughly cleaned? And What's that transparent plastic over the circuit board? (I should also note that someone got inside before me, I can tell from the FM frequency window being glued with gorilla glue and other small fiddling inside it) its my first radio repair so I'm basically a noob. Sorry if the plastic is something very obvious. I would have looked it up by the service manual but I can't find it for that model of sanyo precisely only the 9900 and newer more common models.
