Trace 2424 "blinking"

So... a system that i encountered has a Trace DR2424 inverter/charger on it. This question is about something that happens in inverter mode.

This was working for awhile after i cleaned up the wiring (the previous owner had departed, taking the batteries and some of the wiring).
The system has a totally separate C40 charge controller which seems to work excellently and we installed new batteries and DC distribution.
Its a 24 volt system.

So anyway, worked fine for several months. Then an interesting thing started happening. Although the LED on the inverter would be *on* (and green) the *output* started "blinking" (cutting on and off every few seconds). This seemed to be correllated with battery voltage (ie. low voltage meant more likely to blink).

However now its doing it all the time. We have a secondary inverter in use, but i'd like to know if the 2424 is likely fried, or if this is some failure mode thats well known to others?

Thanks
-jcp-