I'm not familiar with your device and can't add anything regarding the symbol flashing, but regarding your reception of Wx stations, I'm going to ask a stupid question or two, so don't get offended. I find some of the most stubborn problems I come across are usually the obvious simple things that I hastily skipped through because I 'never' make obvious mistakes. When you tested your VHF, was the other station pretty close by? Is it possible the squelch is high and a nearby VHF contact can break it, but the Wx station can't? I'm assuming you normally receive Wx stations in your area. If you turn the squelch all the way down, then manually scan each Wx station, can you hear anything besides static? If you get something very weak, you could have a fault in your antenna system - a damaged coax, corroded connector, or broken antenna. See if your neighbor in the slip next door will let you hook up your radio to his antenna or vice-versa. If you know anybody who is a ham radio operator, ask them to help you check your radio and antenna. If you can't find anything, ask around for a local radio shop that could look at it. You could make a quick test just hooking a different antenna up if available. It wouldn't have to be mounted, just vertical. Tie wrap or tape it to something (not the rigging) just to test. Good luck. I know I pointed out some obvious things, but I would rather feel like I overlooked something dumb rather than have a broken radio.