Marshall Fletcher

Hello, I find myself the proud owner of a brand new, old stock R7623G. This bad boy was still sealed from the factory since 1991.  I need to know what to expect when I power it up (if I should power up). I would suspect that the electrolytic caps have dried out long ago. There are no plug in modules.  I would also like to know what 3 modules (if that many) that I should be looking  to obtain to make this usable?  I haven't used a scope since the early 70's and I am sure that particular scope was a dinosaur at that time.  Looking for any advice or tips.  I do have the users & service manuals.

thanks in advance

fletch