at that age it would be good to replace it weather it blew or not. going from a single stage converter to a 3 stage will be good for your battery life. you can buy a converter like the PD 9245C and just wire it in, but your still going to have the ac breaker and glass type automotive fuses that are getting verry hard to find. I went with a whole power center in my 1991 camper. I used a PD 4000 series and it took a little bit of enlarging the hole (about 1" top and side" but the ability to use mini fuses and have real breakers for the ac instead of just a reset, and the filtered dc made it worth it.