Xantrex RS 3000 just got loud.

I have a RS 3000 which is probably 10 years old. It is in the storage bay below in my 5th wheel. Normally you can only hear the fan run but is fairly quiet and can only hear it when bay door is open. Yesterday it got load, very easy to hear in the bedroom. Sounds like a fan to me that has a bearing issue, but I also see it could just be the converter getting old and the varnish on the wiring being gone. My thought is that it would steadily get louder if that was the case, not just one minute it's quiet and the next it's loud.
I am trying to find out if anyone else has had this issue.
I did turn off charger and it made no difference in noise.

Thanks