Thumping is 100% caused by the 22UF 50v cap directly between the IRS IC and the Output MOSFETS.  If you are hearing that thump,  the IRS IC is fine.  At this point in time, the amount of time the, 'now brown' glue on these amps is turning very acidic when it gets warm. It etchs the copper, and many resistors, transistors, and diodes fall off the boards when the glue is removed.  it's a 50/50 shot at repairing those early versions now.  We probably have a box of 30 at this point,  we threw out just as many back in October.  

McIntosh MC-225, circa 1962.  Updated by Terry Dewick in 2018.  

Well, maybe not. Honestly I dont exactly remember, I did some measurements with a scope, but it was already a few months ago from now. The result was that I decided to just order a new amp section (its not original and didnt include any power source, so the price was very reasonable). Before any of that I also tried replacing basically all of the possible "basic" components (caps, resistor). I read this topic and other sources for all kinds of possible faults. All this didnt help one bit. The fact is that its a total pain in the *** pcb to work with. I've repaired about 10+ different amps before so not a total novice...but nothing has ever been so difficult (to access, work on) before.   Even if its not the IRS IC, I think the power amp is beyond reasonable repair. Might be some other small components on the board, under all that goo and glue crap, but I'm not looking forward to ripping the whole pcb off the backplate. Its glued on there real hard, and besides it has to be airtight at the end.   Do you have some reason to believe that the issue is before the IRS chip? The fault with the amp was that it was making some quite random thumping pulses when powered on, and if I remember correctly did not play any sound from the input.

Anyone know why I cannot upload a 1MB photo?

It sounds amazing. Had a couple serious listening sessions and cried both times. Realized a couple days ago I had my speaker wire backwards. It has arrows on it and I believe this made my speakers out of phase or whatever you call it. Fixed that and they sound amazing thanks for asking. Hope everyone had a good new year and holiday.    Ya I don’t care about blocking doors lol. It would be off to have them set up over there. But doable possibly. It’s something I will think about. But yet both speakers are same distance from side wall. I also added an extra curtain to go behind the front right speaker to match the left side. 

https://maine.craigslist.org/ele/d/freeport-vintage-klipsch-forte-ii/7816952727.html   No aff.....

i would not use a sonos amp with your heresys -- i don't think it would be a good match.  you're better off with what you have matched with a sonos "pre amp".

the "y" means 1983.  sounds like you've done all you need to do to the speaker.  whether a heresy ii or iii or iv sounds better than you speakers is personal.  "most" would say the iv models sound the best -- personally i preferred by 76 heresys with new factory caps.  your heresys can sound quite good with the right amp and set up properly.  i'd sit back and enjoy.