I wanted to give a short report on my upgrade of a Tivo Series 3, TCD648250B, from a 750GB drive to a 2TB drive. The new drive is a Western Digital 2TB AV-GP, WD20EURS. The Tivo is running software version 11.0k-01-2-648, and the System Information for the unit shows up to 318 HD hours of recording capacity. I used WinMFS to copy the contents of my 750GB drive to the new 2TB drive. I had supersizing turned on. I believe I was offered the chance to expand the drive size, but I also used the "mfsadd" function of WinMFS. I used the wdidle program to verify that the WD20EURS already had the IDLE3 function disabled. Important note: Make sure you attach the drive directly to your motherboard's SATA bus. I tried using wdidle with the drive in an external dock that is attached to the internal bus, and wdidle saw the drive, but it kept reporting an error and not showing the IDLE3 state. My biggest problem was that when I put the new drive into the Tivo and powered it up, I'd get the "Welcome" screen for a couple minuntes, along with the proper front lights showing on the unit. Then, the lights would go out, the amber light would flash, my TV screen would blank, and then the "Welcome" screen re-appear. I was stuck in an endless boot loop. But the original drive worked just fine and booted normally. After much fiddling and research, I finally realized that this might be a sign that my power supply was going bad. Sure enough, three capacitors on the power supply had domed, swollen tops, indicating they were going bad. I replaced these capacitors and now the Tivo boots normally with the 2TB drive. I'm guessing that the new drive is drawing enough extra power during boot over the old 750GB drive that the failing capacitors couldn't handle it and induced the boot looping. Hopefully, this will help out anyone with similar issues. Here are some URLs that were very useful to me through this process: Series 3 stuck in "Welcome! Powering up..." loop Bad capacitors in power supply What's wrong with my S3?