I have had my subm (2400watt version) in storage for just a little over a year. I took it out this week to test and on powering it up I get 4 red light sequence. I did email Mark but I guess he’s rather busy, so if anyone has some ideas for some trouble shooting, please let me know. I have tried powering off and unplugging for a day but still the same result. The subm end is connected via RCA connection to AVR.