Re: [CAD_CAM_EDM_DRO] Re: Going home / more stepper speed!

Jon Anderson wrote:

> Bill,
>
> Yeah, I've looked at them on eBay. Trouble is, I just don't know what's
> a good one and what to avoid. I've been told most Tektronixs scopes are
> horribly expensive to have serviced.

Forget servicing. If you have the knowledge, some simple repairs can be
done without manuals or factory parts. Consider buying a used, low price
scope for the home shop as if it were a Taiwan-made toy. You won't
spend enough on it to possibly justify professional service on it! Figure
that we started talking about $150 investment. If you took it to a Tek
service center (which probably doesn't exist anymore, anyway) there's
no way you'd get it looked at for less than $165, with no work done,
and no parts, just an evaluation! So, you take a bit of a chance on it,
hope it works for a few years in very light use, and when it dies, you
sell it on eBay for $20 so someone else can pick spare parts off it, and
you buy another. I would not even suggest this route with many brands,
but with the top-line series of Tek models, you have a VERY good chance
of years of use with it. Avoid Telequipment, a Tek-Sony linkup to
make really CHEAP (in the worst sense) test equipment.

> I'm not exactly sure what rating I
> would need for general use, but would imagine a 40mHz scope would work
> for me. I'm really looking for brand recommendations, preferably down to
> a particular model. Having no real need, I can be very patient on eBay.
> Also of great value however, would be mention of any brands/models to
> avoid.

Given the usual signals one runs into, and the pricing/availability of certain
frequency ranges in test gear, I'd go for 100 MHz. You probably won't
find a general-purpose Tek scope in the 1975-1980 vintage with a
40 MHz bandwidth. There were some oddball, battery-operated mini-
scopes made by Tek with that sort of bandwidth, and I would avoid them.
Not that they were bad, but I don't think they were as reliable as the
465 series. That was really the epitome of a fine instrument, of that
vintage.

I think you'll find that the Tek 22xx series of the same bandwidth will
often sell about the same price as the 465-series equivalent, even though
the 465-series was from the '70s and the 22xx series was from the late
'80s. There's only one reason a 15-year older unit commands the same
price!

Jon