What to do when a crucial piece is in the shop?

Mother Nature is telling you to get out-of-doors a little more often... :-)

You could view it as an opportunity to acquire a new skill; learn a new language, become an airplane pilot, write a novel, clean up your bedroom, etc. ;-)

I am sort of on the same boat. I accidentally tripped on my speaker cable and damaged the driver that the cable is connected to since I hardwire the cable directly to the driver. And, just before that, the AC socket on my transport/cd player broke probably a result from testing out numerous powercords. Well, I am using an older pair of speakers that I am actually selling now and using an old dvd player as transport in the mean time. They actually sound pretty good still.

I just take long elevator rides. The sound reminds me of my favorite pair of full-range single driver speakers and it makes me smile.

So, if you are ever in LA and see a middle aged smiling man loitering in/around an elevator telling people to shoosh, chances are that part of my rig's in the repair shop.

I have a somewhat expensive but useful option for the future, keep two systems active:
-reference system with your best stereo gear
-smaller cheaper 2nd system, can be just small integrated amp and monitor speakers for stereo. Same principal applies to video/HT since almost everyone has more than one TV in house.

Many advantages here:
-very helpful/easy finding problem in main rig if you can swap out each piece with gear in system 2
-can break in cables/new gear in system 2 without tying up reference system for this choir.
-gives you luxury of trying different combinations/types of gear paired together.

Sorry to hear of you current problems and hope everything is resolved soon.