I also disabled the power supply fan which would have pointed into a blank wall on the case and provided very little (if any) cooling. Then I swapped the non-standard top to the old power supply case onto the new case. The non-standard top has ports on top and a baffle to direct air there from the case fan on the NAS, so that will probably work better than the blocked fan would have.
We'll see what happens when I power this up eventually.
Meanwhile, inside the old case, it looks like damn near every capacitor was leaking. Well, that would explain a lot...
In other news, I dropped the two old desktop computers, a laptop computer, two monitors, and the recently replaced VPN appliance off at an Oracle office today. As daisy_knotwise would say, the office feels much lighter.
Now I just need to take care of the mess that had been all over the desk and is now, well, just all over. This will be easier when the open area of the desk isn't full of NAS parts. :)