Do you have a Game Gear with low-functioning or non-functioning audio? Maybe it also has the image of the display with very low contrast or very faded? The problem is with the 99% due to the capacitors to be replaced.
In this site you can find all the information you need to do it, and on eBay you can also find kits of new capacitors ready to be fitted. Alternatively, if you don’t feel up to doing it yourself, you can send the console to someone who will do it for you (the price is around €50, excluding the cost of shipping it out but including return shipping to the sender). The same capacitor problem could also be linked to a console that no longer powers on; in this case other capacitors need replacing.
REPLACEMENT OF ANCIENT SCREEN
If by now you have opened the Game Gear to replace the capacitors then you could take the opportunity to also install the expensive McWill screen (99$ / € only the display + another 50 € of labor !! And, if the question had arisen, unfortunately the answer is no ... in China they don't yet )! A modern LCD instead of the nowadays-considerable-original Sega zoe:
If you want to change both the capacitors and the lcd here is what awaits you!