Csng1, I assume you mean, one should only use identical parts? Do you have your Io for repair at the factory, or locally?
For some reason, mine has failed once more, with exactly the same symptoms. After bringing it back from the repair shop, it worked OK for some days, then I turned it off for a day, and then, starting it, same thing as before. Sadness reigns. Strange how one can miss a piece of gear so much, I guess this says a lot about the Io. I can play a bit of digital, using the volume on the Squeezebox Touch through a Stello mk2 Dac connected directly to the amps - quite nice, but not the same. Not at all (sigh).
Obviously something is causing these failures that was not fixed, and I guess I have to try the repair shop once more. Jim White promised to get back to me on email, but that was some weeks ago - no further info.