HK Citation II with MGIIBs

I am beginning to use an HK Citation II amp, built from a kit by my father about 40 years ago. What is required to bring it fully back to life? Is it likely to drive my MGIIBs happily? Would it co-exist comfortably with my Hafler DH 110 preamp or would I be better advised to try to get hold of the Marantz preamp the HK was paired with in its early years? Is this all folly? Bear with me, as I haven't paid much attention to audio equipment for the past 20 years or so.