Ahhhhhh....my very first receiver. I bought the SA-5170 brand new from Team Electronics in Oshkosh, WI when I was 14, after saving money earned raking leaves and mowing lawns.
Had it through high school and college, lost it somewhere after college...me thinks me gave it to a girlfriend (DOH!). I now own a SA-5370, which marked my return into audio of the 70's, albeit now as 'vintage'.
They have a very distinctive 'odor'...give a sniff above the vent, you'll see what I mean.
Enjoy your garage receiver!!!