There is a Lowrance 350a on E Bay.
http://cgi.ebay.co.uk/lowrance-lms-3...QQcmdZViewItem
Please don't bid on it because it looks just like the one I ditched at the Sedgensworth re-cycling centre near Fareham last week. If it is, the screens fecked. Having previously dismantled another 350a I can tell you the screen is machine soldered to the board by 4 x 64 connectors so you won't be soldering a new one in very easily.
I still have the wires, ariel and sounder in the garage.
Pete