Progressive Dynamics PD4355 would be a direct replacement for what you have. Disconnect battery ground, unplug shore power, turn off generator, open front panel, remove screws and fully remove front panel, remove some wires (mark first) and some screws, slide out old converter, slide in new. Replacing the fuse panel with the new one is a little work, and if you are picky and want to do a neat job you may end up rerouting a wire or two for a better routing and fit, but it comes with a new housing for the converter, so the swap is quite easy. Just went thru this a couple of months ago.
http://www.bestconverter.com/4600-series-Upgrade-Kits_c_133.htmlBestcConverter is a family operation and if you have an issue, they will talk to you evenings, weekends, whenever you need help.
Charles