Hi folks. Trying to bring my good ol' ULD15-II back in service. Paid a tech to replace the surround and took it home ...my ears filled with anticipation. No joy, just some patterns of rumbling, squealing, popping...resetting every several seconds...standby mode? I tried different phono cables...referring to the "short circuit" info in user manual. No joy. I did however notice a rattle coming from the cone. Looking through the holes with flashlight I can see an object flopping around on inside...where that flat 4-wire cable goes through. I assume it is something for feedback or ?....and should be affixed not loose? Anyone know about this or similar problems, causes, fixes? I would sure appreciate any help and expertise. Thanks.