What's this issue I am having?

Hi all! I had a quick question. I bought 2 Sega Game Gears (not working). I knew the capacitors were bad, so I bought 2 sets of new ones. The first one I did (A VA1 Board), went pretty smooth. I changed motherboard caps, and a few sound board caps. Works like new. But the second one (VA4 Motherboard), is a different layout, and had some issues figuring out where the caps went. I even had to use a few from my previous cap set. But in the end, it works great. Except for one issue.....the screen will not show anything until the unit warms up? As it stays on, the screen flickers, then once I assume it's heated, it's solid. Even if I turn it off, and back on again quickly, the screen stays on. Now, if I were to let it sit.....the screen would need to heat up, and slicker until it's warm. Any ideas why it does this? I appreciate your help. Thanks.