Alex,
There might be a few bread crumbs to follow to get you somewhere. It has been 35 years since I have seen an SCD5000 but I believe that the power supply assembly (the box) is similar or the same as used in the 1130x(A) scopes. The SCD5000 has additional and unique converter boards to develop other voltages but the assembly with the fan housing was initially the same as the 1130x(A). Consult the early 1130x schematics at the Tekwiki page. You might be able to determine if it is a match or a close cousin.
Clark
