Welcome fellow newcomer
My brother got an express at launch to play our TG-16 games on. I was so jealous the first night, I had gotten a GameBoy and he had gotten the Express that Christmas Morning. When we went to bed in our bunk beds I remember seeing this glow from the top bunk and was so jealous of his back lit screen, not even considering the quality of games he was playing compared when I could play had my Gameboy been lit.
However, that next morning we were playing our systems, and his ran out of batteries and my gameboy kept trucking. He got another set of batteries, and then began his tirade of gloating again. Needless to say later that day he ran out of batteries again, and the jealousy tables had turned as I was still on my first set (of less batteries) and hadn't needed to bother the parentals for more batteries/money. That is when he made the choice that I regret not discouraging to this day, he decided he didn't want the Express, he'd rather have a system he couldn't play in the dark but could play without needing to constantly ask for batteries or tethered to an AC outlet, so he requested that it be returned and exchanged for a gameboy with games. I still wish we had the express, and to this day want to replace it and relive the memories with it, so now I am jealous of random internet friends! Congrats on the working express, and I hope you enjoy it!