Vintage receivers???

Somebody has to do it.  I went through a phase of trying to buy better Japanese 70's gear a number of years back and found nothing but trouble.  I had a Kenwoood KA-7100,  a 60 watt integrated amp, in my late teens which survived into my 40s.  Went I went to replace it from units I found on Ebay they were all a mess, some misrepresented as working , some not broken at first necessarily but broke shortly thereafter and deemed un repairable.
I then got the bright idea of buying the TOTL  Luxman receivers which I coveted for years and even when old not cheap,  half working, orreally basket cases that were also simply not repairable, for a reasonable price anyway.It sounds Like you are interested in restoring/refurbishing the piece you get.  I never had a reliable repair person, and burnt boards and such are really ridiculously difficult to find in some cases.
However I have had good luck with older units, from the tube era, and have found good success with Fisher and Sherwood.I have had some successes with a solid state Marantz amp 250 M IIRC (just barely younger than the tube units).  I ham handedly made it play a very low ohm load and it caught fire. My BAD! I also really loved a very early Accuphase  pre amp.  Even that dropped a channel but I traded it for other gear to a guy who could fix it.

Well John the Marantz 240 should make a fine amp for you to to recap and refurbish.  If the work is only a matter of caps.  The bigger problems are the integrated circuit boards.  If they are bad you will be out of luck.  Remember that older amps frequently had less power than you would anticipate seeing now.

I am not familiar with the Audiokarma site.  I have used this and Audio Asylum. Do they have a vintage discussion board? Or do they have multiple vintage bulletin boards, and how are they arranged?

I guess I was wrong about the Marantz 240 if 'Kosst "is correct.  I suppose that my reliance on units that still function and my inability to do my own repairs, has made me a cheerleader to those that want to or do.

I wish I had a repairman (no bench in my apartment) Or someway be able to do it myself someday.