Marantz receiver questions

I am not familiar with either of the Marantz units but I do see cheap, crummy speaker binding posts on equipment all the time.   I suggest if you are handy with electronic repairs, open it up and see if the connection problem is internal.   If you are not handy, take it to a good repair shop.  It sounds as if the problem is mechanical, not electronic, and should be a simple fix.

Upgrades - the thing is, your ears learn and improve just like muscles when training.  Given time, you will hear things and notice things that you would not have noticed before.   Only you can decide if the extra kilobuck is worth the sound quality difference but one thing is for sure, don't upgrade if the speaker terminals are the same crummy ones on the PM7001!

What kind of speaker connectors are on the cable? I don’t think replacing the PM 7001 with a PM 8006 is worth the investment!

I've just got the speaker wire screwed on.  Would banana plugs solve the problem?

Yes! Or spades!

Btw, last line in original post is wrong.  It's a PM7001 that I'm thinking of replacing with a PM8006.

Pardon my ignorance, but do standard banana plugs fit with all equipment?  25 year old Paradigm speakers, 20 year old Marantz receiver--they'll plug right in to this equipment?

The PM7001 has binding posts that accept standard banana plugs. Go online and search for Nakamichi banana plugs. They attach by inserting speaker wire into a sleeve and tightened with a pair of small screws. A set of 8 are likely ~$10.  

I find it interesting it's cutting out with bare wires screwed on. That's pretty much as clean a signal as you can get. That binding post might be shot. Have you tried the second pair (system 2) speaker posts?

Same problem with both A and B speakers.