Posted: Mon Jul 09, 2001 5:09 pm
I ran into a similar situation with my Series 30 MCA, which is a couple of generations newer than the 8100 (35 lbs vs 80), but with similar architecture. Mine was dead from the get-go. Fortunately, the engineers at Canberra are very generous with their test points, and I was able to isolate the problem to a bad 12V supply. Narrowing down the problem after that required some board-pulling to isolate the one that was pulling down the supply, then some judicious trace-snipping to isolate the short. This turned out to be due to a bad tantalum teardrop cap ( there must be hundreds used in this box) and a fried 741 op amp in the power supply. Who killed who is anybody's guess. Now that I am close to having a working NaI scintillator setup (I find out this afternoon), I get to find out how it really works.