Recently I took my 73S sporto apart for cleaning. Now that I am getting it back together, the US Frankfurt five button (2 AM/3 FM) stereo radio is giving me fits. AM plays great but when I push any FM button, all I get is a hiss (variable hiss volume using the volume knob). Using manual tune gives the same result- plenty of hiss, no FM signals.

I had the fenders off, but did not unplug the antenna. Could it be that I did something to the antennna when I took the fender off? Does the antenna need to be grounded on the fender (or not grounded on the fender).