[cctalk] PCs Limited XT

I am getting an error message when I boot up a recently donated PCs Limited XT clone. The error is ARC Turbo Board X Turbo System Error # 04 Does anyone have one of these boards, I believe the error means the board has been removed, and the system can't find it/bad board. If so, please advise the $$. I don't think the board is specific to PCs Limted, I found a general manual called "Turbo-XT Main Board" that seems to be the OEM of the PCs Limited-branded motherboard. I assume there is a separate daughterboard the the "Turbo" part. Yes? Thanks Bill