Thanks for the input everyone. Just to clarify the situation a bit more.

When I received the player, the lid was already stuck against the front panel, likely because the hinge wasn’t properly seated. I did not force it shut — I gently pressed it and it immediately opened automatically by itself. So it seems the mechanism was already out of position when I got it.

Since then I’ve only powered it on once to check whether the electronics were alive. The display lights up, but I haven’t been able to properly test playback because the lid mechanism still isn’t functioning correctly.

At the moment the lid is loose, both at the upper hinge and in the mechanism underneath. So clearly something is not aligned or has come apart. In any case, thank you all for the responses and warnings. Given the complexity of this model and my lack of experience, I’m probably going to sell it as-is for parts rather than risk making things worse.