Garmin 430 screen flashes

Anyone else have their Garmin 430 screen flash or blink white on them
periodically. Noticable mostly at nite. Local hanger flying expert says it
is well known and easy fix by any avionics shop. Anyone go through such a
fix and know what's done?

I flew with an 8 yo 430 install which had a continuous milk white bright
screen, and the owner got an internal battery replaced in an afternoon.
Could that be the same?

I want to be a bit informed before calling the avionics shop.