ALot of the PD series converters come with a 120VAC household type power cord.
Only the converter/charger unit needs to be replaced - the power distribution panel with all o f the 120VAC Circuit Breakers and 12VDC Fuses gets left in place. It should have ample space in the bottom compartment for your replacement converter/charger unit to installed in...
I guess this is what you are referring to. if so you can just cut off the plug end and connect the three cord wires to the proper circuit breaker and terminal bus bar connection lugs... I would solder the wire ends before pushing into the screw down type lugs.
I was glad my PD9260C converter/charger unit came with the 120VAC plug cord. I istalled my unit standalone as close to the battery back as I could get. Then I just plugged it into a close-by 120VAC receptacle.
Roy Ken