Been running a Dual 1229 table with Shure M91ED cartridge for many years. A while ago, the right channel started dropping out. I was able to get it back by re-seating the headshell in the tonearm. Now the right channel is gone and won't come back. I tried swapping the leads in the headshell, and the problem dutifully jumped to the other side (left channel out). Next thing I tried was disconnecting the R and L leads from the shell and letting them dangle, then replacing the shell in its seat. I was able to touch each lead in turn with a finger, and got the expected hum from each side. Reconnected the leads to the back of the cartridge, no right channel. Does this mean that the M91ED has gone bad internally? Has anyone had a similar experience? (I also tried swapping in a spare headshell that had an M44 in it, which worked fine on both channels, so I don't think it's the connection in the arm itself.)
