I have this exact same problem now. Were you able to get yours fixed, Chris? Richard just quoted me $200+ to fix plus anything else that may need attention. It still works liek yours, but the output is about 15db lower than my good amplifier.
I can just buy a new body for less than that price. I may see if a local computer repair place can fix it for me if I can still get the part.
I never fixed it. Sold it as is and moved on. Already had pair of 480’s.
Gotcha. I'm going to hold on to my working 460 to use as a center omni. I just received the part from Harman today to repair the broken 460 so I'm not sure what I'm going to do there - probably just stick it in a drawer for now.