More detail. Radio and CD work fine on 12V
but sound comes and goes when using shorepower... and the coming and going is not predictable. One time, just plugging in kills the speakers, another time it doesn't. Plugging in a vacuum brought silence once but not other times. Starting the vacuum has also started the sound and vice versa. Once, the sound quit after about 10 minutes with no stimulus whatsoever. Could this be a grounding problem? There was no apparent ground wire in the front overhead cabinet where the old 8 track was installed so I spliced a ground wire on to one of the front couch reading lights (from the same circuit). Looking for insight on this one. Thanks.