Never run a 7100, 8100, 8150, or 9150 without a PDS video card or a PDS terminator. This can damage the motherboard. If the video card goes bad, you can replace it with another video card or use motherboard video after installing a PDS accelerator or "Apple Terminator, PDS, WGS 81XX." Workgroup Server 8150 and 9150: PDS Needs Terminator, feedback from Mac Managers list, and personal experience.
I guess that card would be from a Radius 81/110 then...Q: What is the small card installed in the slot next to the NuBus slots?A: That is the PDS terminator. It is required to terminate the NuBus slots. Cards installed in the 81/110 may not operate correctly if this terminator is removed and no suitable alternative, such as an Apple AV card or HPV (or VRAM expansion) card, is installed in its place.