Re: Use a scope to determine overvoltage needed for stepper motors

paul@... wrote:

> From: paul@...
>
> I have to admit a bias, but I really like Tek scopes. I have a 453 that
> was obsoleted in 1971 and it's still going strong. It's a 50 MHz scope
> with sufficient bandwith for just about anything except high speed digital
> work. I have seen these selling on ebay for $75. Not bad for a scope that
> cost $2000 in 1969.
>
> The 453A series has a slightly larger screen and was built up to '75.
> The 454 series is a 150 MHz scope; similar features, just more
> bandwidth. This series is more or less portable at 30 pounds; the
> handle also serves as a stand to tilt the screen to a comfortable
> angle.
>
> Between the used equipment dealers, ebay and Ham swap and shops, you can
> get a perfectly usable used scope anywhere from < $100 to a couple of
> thousand depending on shape, calibration and features.
>
> I'm currently looking around for a 7900 mainframe scope. Those things
> use plug in modules that can do almost any imaginable measuring task.
> The 7900 has a 500 MHz bandwidth and can go higher with the right tweaks.
> Current ebay price seems to be in the $400-600 range.

Unfortunately, all of these are real-time scopes, and are very poor for
very slow or one-time events. I use a real-time scope a lot, but for servo
tuning, etc. they just don't do it. Real storage scopes are finicky, and the
CRT tubes cost much too much for a hobbyist to replace, if they go bad.

For these kinds of applications, a DSO of any sort just can't be beat.
We just got a Tek TDS3054, 4 ch, 500 MHz bandwidth, 5 GSa/Sec,
Digital Persistence, waveform math, everything you could ever want.
About $8975 (University Discount). Well, a LOVELY instrument,
but only Bill Gates could afford it for hobby use!

A scope like this would have cost about $45000 just 5 years ago!

Jon