The amount of amperage required to supply enough power to fully operate everything on your RV depends on the number of 12 volt lights, fans, etc. your unit contains.
Using an RV power converter with more amps than needed does no harm, but utilizing a smaller converter may cause occasional tripping of the 12 volt breakers if too many of the 12 volt lights, fridge, etc. are used at the same time.
Unless you know the amperage your unit uses, it is better to replace it with the same amperage converter.