I have one
that cost me $2.00 at a Ham radio flea market. It works with the transducer that came with my 1976 Catalina 22. If you have the power connector, your in luck - I had to make one up with molex socket pins and shrink wrap. It uses 12 VDC, the polarity is marked near the power pins. There's also an RCA plug for the transducer. Any old-style transducer will likely work. You don't need to use the record feature. Set the chart speed switch to the center position (off) and fiddle with the sensitivity and D.R.R. (?) controls until 2 flashes appear; one at 0 and the other at the depth.
