Concerns purchasing Vintage System?

"What should I be worried about?"

Going in, pretty much everything. That stuff is good but old.

You'll have to assess it piece by piece. The actual value could vary widely depending on condition.

You won't know what it is really worth until assessed properly.

If there are problems, most can probably be addressed properly in that that the companies are mostly still around. The Tandberg is a fantastic piece but likely the most problematic, but SOundsmith in NY state is historically the go to place for Tandberg repairs these days, maybe still?

Definitely check agon blue book values and pro-rate based on known and reasonably certifiable condition at any particular time.