Do you have a meter? I'd suggest to see if the converter has 120V power to it. Then, measure for 13V power at the output.
I believe the circuit breaker is internal to the converter (on circuit board?) and is auto-resetting.
In any event, having a bench tech fix the Magnetek is still going to leave you with a charging device that is subpar and will probably cost nearly as much as a new converter. If you know what you're doing, you can replace just the charging section of the load center or replace the whole converter and load center.