Other useful test equipment (was: RE: Scope use...)

From: Corda Albert J DLVA <CordaAJ_at_nswc.navy.mil>
Date: Fri Jul 21 13:30:27 2000

Another useful piece of equipment is a multi-channel
logic analyzer. Most of these units can read out
pulse-timing directly, and will provide an invaluable
way to display TTL signal patterns and relationships.

  Now, before anyone flames me, I will admit that
new versions of these can cost multiple thousands
of dollars, but I've noticed that a significant
number of older units are showing up at hamfests
for << $200. (I ran across a Tek. DAS analyzer at
the Trenton Computerfest for <$25.00)

  These older units are becoming useless for
new and/or cutting-edge hardware development,
and are being dumped by a number of hardware
development firms, since most of them can't
sample systems with clocks > ~10-20 Mhz reliably,
but for the kind of antique-system tinkering most
of us do, these can be quite a help! The one thing
you should look out for when buying one is to
make _certain_ it comes with a set of test
pods/cables/probes. A podset can be impossible to
locate after the fact, and may cost you a horrendous
amount of cash if you try to order them from the
original manufacturer.

  Also, I suggest that you stick to analyzers made by
larger companies such as HP and Textronix. You'll
have better luck finding docs and getting help
from other hobbyists that way.

-al-
-acorda_at_1bigred.com
     


> -----Original Message-----
> From: allisonp_at_world.std.com [mailto:allisonp_at_world.std.com]
> Sent: Friday, July 21, 2000 1:17 PM
> To: classiccmp_at_classiccmp.org
> Subject: Re: Scope use...
>
>
> hi,
>
> think of an oscope as a graphic voltmeter that plota against time.
> the X axis is volts and Y axis is time.
>
> That is along way from troubleshooting with one. To trouble
> shoot with one
> you really need to have some idea of waht you can expect to
> see vs what
> you actually saw. Most prints do not automatically give you that.
>
> While a scope is handy, for fixing machines that were
> formerly working a
> DMM and logic probe tend to be more useful. Exceptions exist
> like setting
> hammer flight time on charaband printers or slice levels and
> timing for
> older core stacks. The latter being adjustments rather than
> fixed by rules
> of logic.
>
>
> Allison
>
>
> On Fri, 21 Jul 2000, Bill Sudbrink wrote:
>
> > I was going to post this request sometime, John Fousts
> > post has inspired me to do it now. Anyway, I have also
> > recently acquired an oscilloscope (Tektronix TDS 3012)
> > and, while I have all the documentation and some notion
> > of what an oscilloscope does, I really don't know how to
> > bring it to bare against the several dead/flakey systems
> > currently in my possession. I hope this message will
> > start a "how to use an oscilloscope to diagnose vintage
> > hardware problems" thread.
> >
> > Thanks,
> > Bill
> > (by the way... bills_at_adrenaline.com is now my email address)
> >
>
Received on Fri Jul 21 2000 - 13:30:27 BST