Need pointers on Oscilloscopes

Since you're going for a second-hand one (I think this is wise), buy a well-known make. IMHO Tektronix are the bext. Older Tektronix 'scopes (certainly up to the 465, etc) had excellent manuals with schemaitcs (:-)), theory, etc. Make sure you get one (or can get one). You will need it. Although I like them, probably steer clear of the 500 series. They're large, hot (mostly valved), and take a bit of TLC to keep going. Great if you like that sort of thing (I do). Make sure you know the spec of the instruemnt (Do you have a portable machine with a wireless internet connection to the web, etc? If so, take it along and do a serach on any instrument that you spot. I've seen people do this). The reason is that Tekky (and others) made some excellent special-purpose 'scopes that are really not suitable for computer repair. -tony