Originally Posted by PODIII
I recently purchased a 4XL and sold my two older HD units; I moved two of the TiVo expanders without incident to the 4XL and one of the series 3. The last unit would not pair with my 3rd Series 3. I had replaced the original WDC HD with a Hitachi and it had been functioning for years. I tried all the permutations for booting up and the TiVo would recognize the drive- even knew that it was a Hitachi, but would blow by the 3-Thumbs screen and return the message that the unit was not compatible. I spoke with WDC and the tech said SATA is SATA, shouldn’t matter. But, I replaced the Hitachi with a 1TB WDC and had the same issue. TiVo says that it has to be a specially blessed WDC TiVo compatible drive although I can’t find any part number that meets this criteria. I’m at the point of diminishing returns- barring a solution from the forum.
The TiVos which are newer than the original Series 3 (the TCD648250) have a very short list of Western Digital hard drive model numbers which they check when an external is connected.
The 500GB and 1TB WD eSATA external drives specifically marketed for use with the TiVo (hence the TiVo logo on the box) will have one of those models inside.
Somebody posted that short list here a year or so ago, but I can't find it now.