Congo Jr

We have a Congo JR on our desk which seems to not go past its initial boot sequence.
The front display displays the Congo JR logo but doesn’t do anything after that.
To start with the desk bleeped 3 times, but after I reseated the graphics card, it no longer bleeps, but still fails to boot fully.
Could this be a graphics card fault?? It’s a very old DMS-59 dual monitor card....