Hey Hitec man,
Since their is probably no warantee on your Jr unit, why not do what others do who wind up with a lone JR in their collection, just reverse the polarity of the charging jack, then the JR will be compatible with all your other Tx's, that are wired in the more common method. Wouldn't be a bad idea to put a sticker next to the jack stating the polarity change
Regarding the Cermark charger, John, don't forget Murphy's law
Regards,
Pete