Be careful about changing parts...
I'd be careful about changing out capacitors and other parts - if they have failed then you have no choice; but you might find that changing an original part for a new equivalently spec'd part changes the sound. I think many parts were chosen (in the good old days) not only based on specifications but they were also "voiced" (ie, listend to) - specs alone don't tell you everythying about sonic characteristics. Much of the magic of the vintage gear being discussed here is that these units were designed and manufactured by firms that had a passion for what they built - and that included listening to the gear and not just measuring specs.
I'd be careful about changing out capacitors and other parts - if they have failed then you have no choice; but you might find that changing an original part for a new equivalently spec'd part changes the sound. I think many parts were chosen (in the good old days) not only based on specifications but they were also "voiced" (ie, listend to) - specs alone don't tell you everythying about sonic characteristics. Much of the magic of the vintage gear being discussed here is that these units were designed and manufactured by firms that had a passion for what they built - and that included listening to the gear and not just measuring specs.