Pioneer home system value

If in fully operable condition, offer $1000.00 for the whole set, maybe up to $1200.00.  But be prepared to invest time and $$ to make it really good. The sspeakers basically suck in their stock configuration, but there are people who have published fix-it plans online that transform them into credible performers. The receiver will need extensive restoration to be “good as new”, and that will cost. Before buying, inquire locally if anyone does this work. Many areas are “service deserts”, but you may live near someone who has the ability. 

Some vintage gear, especially that receiver, sometimes go for outrageous prices...vintage Pioneer is highly valued by many...

The HPM speaker series have a following. Apparently designed by Bert Locanthi of JBL.

+1 @ghdprentice, although I think he's a little on the high side. 

I remember my Pioneer SX-850 from that period.  People now buy this gear only for its looks, and nostalgia.  Japanese designers of that period designed for specs, and did not listen to the result; the sound would be inferior to modern equipment.  

Possibly with an exception for the tt, if you like the sound of old direct drives.  they were almost universally displaced by belt drive models for a reason, except for old Thorens and some Garrards.

JBL's from that era were almost all terrible.  Speakers now are designed with computer modeling, and listening tests, and are much, much better.  

My dad was a rep for Pioneer in the 70s. He gave me a spec 4 amp and a different preamp which I can't remember the model. I took them to a local shop and had them all recapped. They are connected my old vandersteen 2CEs. The system doesn't compare to my main system but I gotta say, it sounds pretty darn good. He also gave me a pair of HPM 60s. They're very 70s laid back sounding. He's got a pair of HPM 150s with the omnidirectional tweeters they sounds pretty good. As others have said, newer gear is probably better but there's a warmth that comes from that old gear that's super pleasing.