[CA] [CA11] DSM360 Problems

[seeray96]

My 1995 SeaRay 500DA uses an Airmar B60-200-Ray 50/200 mHz transducer, which feeds a DSM 360, connected to an E125 Classic mfd.
In recent years, I've had issues where the depth fails to register on the E125. In the upper right corner of the screen, the transmission waves from the boat show downward, together with a fish icon. However, the DSM 360 led is amber and the Databar shows no depth.
I used to get the green signal, then I'd get the green changing to amber, and last year 90% of the time the led was amber.
I sent the DSM360 to Raymarine for evaluation, but they advised me they found nothing significant. They updated the software and replaced the power connecter and cable. No change.
I guess I could assume a defective xducer and purchase a replacement, but that may not be the issue. Do you have any suggestions on alternative testing?