It means you need to get rid of the Prosine 2.0.
Seriously, I think the code is a relay error code. I went through two Prosine 2.0's a few years ago. The first one was replaced by the factory under warranty (even though it was bought off Ebay, so good on Xantrex for that). But, as you can imagine, it was still a PITA to replace. When the second one went, I ripped it out of there and when all 'Office Space printer' on it, complete with the pimpmacdaddy rap
music blasting from a friends car. (That was satisfying.)
I was getting the same code, along with many others, but I do remember 3073 and I think that was one of the most common. It has to do with the relay that allowed AC to pass through to the
boat circuit.
I think what happened was, when they first released the 2.0, there was a
safety issue, possibly having to do with GFCI and they fixed it with
software. The result was that the system became much too sensitive to tripping and you would eventually get that code. It was safe sure enough, but all
electrical devices are safe when they don't do anything. Shoddy engineering that should have never been released. I haven't bought another Xantrex product since and I don't intend to.
I ended up putting in an Outback inverter/charger and it has worked great for three years now. It's not marketed to
marine users but the critical
parts are all completely sealed up from the
environment so that should be pretty robust in
salt air.
Good Luck