I'm sure unitron will be here soon to give you actual guidance, but you have brought to my mind a story and a joke. The story: Some years before I started working for him, one of my former bosses had a problem with an 844-21 disk drive. So he decided "to pull the engineer technique" and started swapping packs around. He ended up with 3 dead drives and 6 dead packs. You see, the original problem was that there had been a head crash on the first drive. Putting the bollixed up pack in another drive caused its heads to crash. Putting a good pack in a drive with crashed heads destroyed the pack. They had to "fly heads in from all over the country" to fix the dead drives, buy new packs and restore from backup. I am not sure if he was a CE at the time or an OS analyst, which is what he was when I went to work for him. Yes, I know the two situations aren't exactly the same since you were swapping entire drive assemblies, not just disk packs, but the concept is the same. It is a bad engineer technique. For a TiVo, at most you might have tried putting the drive from the dead TiVo in the working one if you didn't care about possibly losing all of your settings and recordings. I would never put the drive from the working TiVo into the dead TiVo. The joke: How many CEs does it take to change a tire? Spoiler 5. 4 to hold the car up and 1 to change out each tire until he finds the bad one.