So I've been riding around with no AM reception for about a year. No biggie except right around the shop I can't get a couple FM stations I listen to. They do simulcast on AM so I finally decided to do something about it.
Discovered that the center wire of the 90 deg. antenna plug was broke. Took it apart, stripped the coax back, slipped the wire into the wee stem, reassembled. Back to normal.
Sorry, didn't take pictures.