I thought I'd read something about this problem in the archive, but I cannot find it now.  The original Garmin GM20 (?) unit we have for wind/depth/air & water temp/speeds is still workiing fine (the 586s fried out after doing an update on a chip, but I'm just using Navionics on the smartphone instead). 

What is not ideal is the depth readout which rarely stops flashing and 'gets stuck' at various depths for long periods when cruising in deep water, then works less than ideally in shallow waters with erratic changes between blinking -- but more or less correct.  After our grounding and C-Tow rescue last weekend I thought I'd look into trying to get it working WITHOUT the constant blinking on and off of the readout.  I've tried messing about with the wires coming out of the transducer without any change.  The outer face of it is clean.  The connection to the monitor is fine.  Any suggestions?  Many thanks!