mark. i had the same problem a few years ago. turns out when sunfire repaired the unit, it was a couple of components that had to be replaced on the amp board. the $275 was well worth it to me at the time since they also warrantied it for another year and upgraded it from a MKII to an MKIV. (my unit blew the driver once and blew the amp once only because i drove it so hard to test its limits.) i've since had no more issues with the unit - still rocks after almost 10 years. i've also since calmed down my urge to test its limits since i now have the signature sub also.