DSM300 stops reading bottom

[OviV]

I have a DSM300 that has been trouble for as long as I have owned the boat. It would often stop showing bottom even while anchored and I would just turn it off and back on or sometimes turn off the screen that was showing sounder data and back on and it would read again. Lately it has gotten worse. The bottom display will freeze, I will turn off the sounder and back on, it will start displaying again and then freeze again after about 30 seconds. The screens will sometimes report that pings are disabled.

The sounder has good power with its own switch on my panel where I can turn it off and on. It does not appear to be hot when the problems occur but if does seem to happen after it has been running for sometime. I have checked all of the connections and all (power and network) are tight and clean. It is connected via an HS5 switch to 2 c95 screens. Screens and sounder have all been upgraded to the latest firmware.

Any suggestions?

Ovi