The depth sounder on our 1978 San Juan 28 dates from around 1983. It's
a Standard Communications DS-1. I suspect that company no longer
exists. We get crazy readings or blanks in both deep and shallow water
whatever adjustments we make. The alarm works only too well so it
thinks it's detecting something. The electric connections all look
good and clean and the PO has always painted around the transducer,
not over it.

I'm happy enough to buy a new unit but would rather not mess with the
through-hull transducer (which looks fine from the inside). Does
anyone know whether a 2008 depth sounder is compatible with a 1983
transducer, or how to check?

Thanks in advance

Richard