u/tomnom

Obviously a Sunn Coliseum Bass head but I can’t find much information about it online and was curious if anyone has seen these before? It currently powers on but doesn’t produce any sound when plugged in to the cabinet. When the instrument cable is plugged in and you tap the jack you can hear that, but nothing when the instrument itself is plugged in. I haven’t played it in years and I’m looking to sell it at this point. Any advice for repair if I decide to go that route?