Should we rebuild MX 300 NavCom

We have an MX300 in our 172 that has started producing squeals and static
whenever it is turned on. It was intermittent a month ago and proceeded to
being continuous. We can still transmit and receive if we can stand
listening to the noise.

I turned it on today and could clearly hear a commercial station mixed in
with the squeals. It also has some LED segments that no longer light.

We've wanted to replace this unit for a long time so as to have two radios
that match but the panel rebuild required by the fact that it is physically
larger makes the whole project more than we can spend right now.

This radio has not been cleaned, tuned, or even opened up for a long time.
Is it worth sending it back to the factory for overhaul or should we just
turn it directly into a paperweight and live with one radio until we can
afford another?

Wild ass guesses and pithy opinions appreciated.

--
Roger Long