You have two options.
Solar & or a new converter.
I just posted a similar question concerning Solar a few days ago concerning my needs & it was recommended to me, 100 watt solar as bare minimum with controller.
As far as the converter, I would replace it no matter what. I also have a Magnetek in my 2000 TT & it is absolutely useless for charging.
I recommend a 9200 series Progressive Dynamics converter with a built in Wizard smart charger.
On another note, never let your coach batteries get below 50% discharge. Get & install a meter of some type that monitors the batteries & tells you the SOC. Do not rely upon the coach monitor panel for the batteries. It is VERY inaccurate.
If you run the generator 3-4 hours per day,whenever boondocking & after installing a new converter you should be good to go. When connected to shore power, you won't even need to run the Genny.
Call these people & tell them what you have & they will recommend a replacement converter.
BEST CONVERTER