[I think it's broken]

I ordered an ADG612 on Monday from Mouser and it came yesterday. I put in the new part, ran the calibration, and everything works great. 

Thanks for the help, Attila.

[I think it's broken]

You were correct, attila, it was the mux. After confirming with measurements, I cut pins 10 and 15 to be double-sure it wasn't the buffer. 

I'm ordering anther ADG612 now.

After going over all my measurements and checking everything I did, I am confident that I did not damage the mux. I don't have anything over 9 volts on the bench, and I did not have a mis-matched ground problem anywhere. It just died of its own accord.

[I think it's broken]

Agreed. I'm checking it out now. I didn't know if it was the mux or the buffer, but on your recommendation, I will concentrate on the mux.

I'll let you know.

[I think it's broken]

I have an AD2 that I use a lot and today the Channel 1 started showing an input voltage of -21 with nothing connected. Channel 2 and all other functions work great.

I restarted the computer, updated the software, and power cycled the AD2. No change.

I calibrated the waveform generator and then the scope, but scope calibration failed saying that Channel 1 is showing too high on the input when grounded. I tried reverting to the factory calibration, but the symptoms remained the same.

So, is it truly broken? If so, is there a way to repair it?