I have never heard a normal logic probe called a logic dart. The LogicDart (I think that's the right capitalisation) is a lovely little instrument, originally HP, then probably Agilent, and I think it's now made by Fluke under license. It's a handheld tool which can be used as a logic probe 3 channel logic analyser, or diode/continuity checker. The most useful mode, IMHO, is 'investigate' In that mode, it works like a logic probe. You only use one input channel, you have one probe to tap on the circuit under test. There are red and green LEDs to show 0 and 1 on the probe tip. It displays the DC voltage at the probe tip (good for checking supplies), and the frequency (determined by number of threshold crossings per second). It's not a good DVM or frequency counter, it only displays 2 or 3 figures in each case. But it's good enough to tell if you're looking at the 5V supply or the -12V supply. It'll tell you if you're looking at the 10MHz master clock or the same clock divided by 4. And hit a buttone and it'll sample the signal and display it -- a bit like a 1-channel analyser. Of course the sampling rate _and the thresholds_ are user selectable. I won;t do everything, but as a first tool to start sorting out the problem it's excellent. The only disadvantage is that it's not cheap... -tony k