AC instead of DC adapter connected to Visioneer 7100

I bought a Visioneer 7100 flatbed scanner (without a power adapter) at a thrift store. I was able to test it at the store with an appropriate adapter (12VDC x 1.25A) and the lamp came on, so I figured the scanner was good. When got home I found a 12V-1.25A adapter and had the scanner hooked up ... in less than about 30 seconds after plugging it in and turning it on I heard a 'pop' or 'snap' from the scanner, and I unplugged it. I turned out that I had used a 12V -AC- adapter; I tried it with a 12VDC-1.25A adapter and it didn't work at all. I took the scanner apart and inspected the lamp inverter card and the card that the CCD is on, and I didn't find anything that appeared to be burnt or bad. There's a third board that's covered on the component side with a metal shield that has to be unsoldered to be removed - I didn't find anything suspicious on the underside of the board. I can't tell if the CCFL is bad or not. What do you suppose is wrong with the scanner?