<> I know the 20mhz B&K would be more than enough to track 8F core problems < <Sure... But if you're buying a 'scope, it makes sense to get one that <will do all that you might need. So while you don't need a 50MHz 'scope <or whatever to sort out 8/f core memory, you might find it worth getting <one for other work. Hence the B&K 20mhz. I do a lot of slow, audio and assorted control stuff that doesn't require a fast scope. My MS15 (bought used 22years ago) is so I have battery operation for portable use. <You don't _need_ expensive test equipment. I've done a lot of fault <tracing using a cheap analogue multimeter and a Radio Shack logic probe. <And with those 2 instruments I managed to extract enough clues to the <fault to replace the fault component first time (most of the time). ;) so happens... <However, I am also sure that there are people here who could use some <more clues as to the fault, who can't interpret every last piece of <information that they can get from simple instruments. And those people <generally make use of rather more instruments, which perhaps aren't <strictly necessary... There in lies the problem. Sometimes the test setup can cause error. Good tools are a must, but good does not always mean the "best" only that is be fully working and calibrated combined with the knowledge to use it. The key is what ever scope is used to know and understand it well, and I mean very well. Generally this applies to many instruments. I happen to do better than average because back when I couldn't afford I had to make do, that meant getting the most and then some. That and over 30 years of experience is particurally handy at times. Oh, the 465 I had, I sold it real cheap to someone I thought could really use a good scope. He dropped it. ;( Allison