Start with which one is most complete, but know the following about the 466. The 466 is a 100 MHz storage scope with all the features of the 465. It has two channels, and a delayed timebase, trigger holdoff. It is, however, only capable of storage at a bandwidth of about 10 MHz.

I'm not familiar with the TAS485, so I won't comment.

I have no hands-on experience with the 2445, but I have used the 2465, which is similar but of 350 MHz bandwidth. I have a 2467B, which is a 400 MHz 4-channel oscilloscope of considerable quality. It is still possible to have it serviced through TEK, as I imagine the TAS485 is as well.

I'd be surprised however, if the TAS485 doesn't have some features that the other lack. A little time on Google, and perhaps at TEKTRONIX.COM might shed some light. The one on eBay that I saw was obviously defective, however.

I'd suggest you take time to familarize yourself with the features, and, as I previously recommended, make certain that there aren't accessories/components that don't come with the 'scope that you'll need but may have difficulty getting.

There's really no rush. More instruments will be there tomorrow.

RE