There are two small indentations at the bottom, which you have to use to open it.

I myself have found that motherboards have system switches with which dual mode Display can be switched off and on, this is on by default.

I have a two compaq portable 3. Both won't boot and show no screen. I can see one of them trying to boot from floppy disk. Unfortunately no screen. I see that there is an RBG output and I connected my Ega monitor. But maybe you need to create a certain keyboard combo that will use the external …

Came across this maybe it will help you. https://www.retropaq.com/the-beginning/ "Dead lines, or lines that show up as excessively bright are problems with old Gas Plasmas – these are problems with the very delicate IC’s driving the screen, they are very delicate and sensitive cannot be easily …