Some questions about early 70's equipment

[Cat3TRD]

Hey guys,

A friend of mine asked me to help them test some audio equipment, to see what works and what doesn't. They have a garage full of stuff.
I was told that from the stuff that works, I could piece together a system as my "pay". I'm not too familiar with some of these older brands, and i was hoping someone could sort of point me in the right direction.

I wrote down the brands and model numbers of the best looking/working pieces. Most of these are receivers, and there's also two turntables.

Starting with the receivers,

Panasonic RA-6600 -best condition
Sansui 9090DB -one of the lights is out, but otherwise fine.
Pioneer QX-747 -again, one light's out, but otherwise fine.
Marantz 2015 -nothing wrong with it, just surface scratches.
Marantz 2275 -I haven't seen it up close yet, but it looks pretty clean. I'm pretty sure it'll work. (It's tucked away across the garage, and we haven't cleared a path to it.)

and the turntables,

Pioneer PL-518X
Pioneer PL-8

If anyone knows anything about any of these, please let me know.
I've searched for each one individually on the net, and couldn't find any reviews for any but the Sansui 9090DB and the Pioneer QX-747. The QX-747 received a bad review. The 9090DB received a good review, was called the last good Sansui.

thanks!
-Justin

PS: I've got to pick out my setup on Saturday the 6th.

Edit: I've decided to go for the 9090DB as the receiver.
Still can't find anything at all about those turntables.