My first-ever eBay purchase arrived today!
Yes, it's capital equipment - a spiffy slightly-used digital oscilloscope. Four channels, 500 MHz analog bandwidth, 2 Gsamples/sec, color display, all those goodies.
The included probes are (as advertised) a pair of P6131s, OK for verifying function, but at some point I'll really be needing four matched probes with better bandwidth - so, it's back to eBay to bid on that quartet of P6137s. (The correct probes would be P6139s, but at $330 each new, I'm not about to buy a set of those new. P6137 is close enough for my foreseeable needs (400 MHz bandwidth), and maybe I can get the set of four for less than a single P6139.) A P6205, 750 MHz FET probe would allow for detailed observation of the occasional really-high-speed (or unusually waveform-sensitive) signal.
I expect it to get some use in the next few days, not exercising the bandwidth, but using the four channels (my other scope is a 2-channel portable). Having multiple channels is good when you're bringing up a full-bridge motor driver....
Update:Got the P6137 probes. There's one little detail: the TDS 500 series scopes (this one's a TDS 644A) have lower input capacitance than the lower-speed scopes like the 2400, for which these probes were designed. Thus, the scope shows overshoot where none exists. Tweaking the LF COMP adjustment to give a flat top on the calibrator waveform corrects this condition.