KIM-1 repair advice wanted

As some of you know, I'm helping with an exhibition of classic machines in the Department of Computer Science -- for Open Day tomorrow (Friday), and running conducted tours on Wednesday as well. Well, one of the supposedly-working exhibits is my KIM-1, but it died this afternoon. I can't get it to do more than occasionally display a single zero, on the leftmost 7-segment display. A cursory look with a logic probe (and no docs to hand) shows the clock is running and at least a few address lines are too. I bet it's a memory fault. What are the common faults? I'm hoping it's one of the 2102 RAMs, because I stand a chance of having a suitable replacement. However, I fear it's more likely a 6530, and I assume they're unobtanium. Has anyone ever come up with a kludge to effectively use a 6532 (and are they any easier to find?) with an EPROM? Or anything else? -- Pete Peter Turnbull Network Manager University of York