Dittel radio Q

My FSG-60M worked fine in my panel last season. During pre-annual
checkout, it powers up but Rx/Tx produces nothing but static on any
frequency; almost like the antenna is not connected. My handheld works
fine on the ship antenna. I tried powering the radio circuit with a
power supply set to 14v with the same results.

I pulled the radio from the tray, and removed the tray from the panel.
The radio works fine in the tray when the tray is not in the panel.
When I reinstall the tray into the panel, the radio again powers up but
Rx/Tx nothing.

I'd like to buy a clue, please.

Ken