Seeking advice on Tiffin 28BR Inverter replacement

[mr.precision]

While hooked to shore power in a camping area, our main TV turned itself off. We then noticed a "pulsing" of the interior lights and a "chirping" sound coming from the TV inverter.
Our 2011 28BR is fitted with (2) 450 watt inverters. One powers the TV's and one powers everything else. When I turned off the TV inverter, the pulsing lights stopped, as did the chirping sound. Although the interior lights do not run off the TV inverter, apparently there was enough current draw to cause them to pulse. At least that's how I see it.
Several website articles state that 450 watts is insufficient for the TV's, although it apparently worked just fine for 7 years.
I would like advice from the forum regarding (1) is the inverter worn out, and if so is it fixable (2) should I replace with a larger capacity unit, and (3) recommended replacement unit that fits without a bunch of modifications.
Thank you in advance for the help.

[dmanpearl]

Hi Mr. Precision. I have a 2015 version of the same model (Tiffin Allegro Breeze 28BR). Although I have only one inverter, it is also small and only powers the plugs leading to television equipment, so I am also interested in any upgrades you decide upon.

You may also want to replace your house batteries and/or upgrade if you beef up your inverter(s). Unfortunately, it won't be easy to fit any additional batteries because of limited space for them inside the entry step.
- David