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 screen? Or does it not work with an EGA screen only with a CGA screen?
Who knows?
Or has any possible solution for my black screen?

Thank you very much for your effort,

Samme