OT (sortof) wanted items (cart & logic analyzer stuff)

From: Dave McGuire <mcguire_at_neurotica.com>
Date: Sun Dec 31 14:57:07 2000

On December 30, Richard Erlacher wrote:
> What kind of equipment to you intend to work on with this new LA? I've used

  Just general hacking. I'm doing more and more digital stuff (mostly
PIC-based) and up 'til now a logic probe, a pulse generator, a DMM,
and a fast 'scope have been all I've needed for troubleshooting. I've
just been thinking a decent multichannel analyzer might be a nice
addition to the bench.

> the HP 1630 though it's been about 15 years. It has some nice features.
> With today's fairly flexible (I/O) devices, however, you might find it
> interesting to build one that uses your PC as a display and acquires the
> sample memory contents from the device via the EPP. If you're really
> ambitious, perhaps USB would be appealing. It's certainly popular enough.

  Eh...that would mean getting a PeeCee. Thanks for the suggestion
though...it's definitely a cool idea.

> If you're determined to buy a logic analyzer, the crux of the task is to
> find a unit that's not only fully functional but also fully complete. You
> need the documentation ... all of it, and you need the complete set of pods
> and whatever mechanism, usually an interface board, that is required to
> support it. You'll ultimately be disappointed if it's possible to have more
> channels than what you've got, so it's important you have enough channel
> boards, pods, and probe clips to support them all. There are usually pod
> testers that come with a new logic analyzer, and those often are the first
> thing that gets lost. Those are extremely necessary when you're having
> trouble gettin a setup to work, because they're the only way you have of
> restoring your confidence in the instrument. If there's some sort of method
> for storing and processing the sample data, either internally or externally,
> you certainly will want that capability. A spare pod is pretty useful, too,
> unless you think you will find one, which I, having searched the market
> pretty thoroughly at various times, doubt very much. I did find on,
> however.

  Understood. I have pretty good sources for test equipment and docs,
so I'll be able to shop around a bit, and try-before-I-buy.

> I've had several logic analyzers, and, in '92-93, due to the need for
> portability, decided to replace my bench-bound model for a portable, a TEK
> 1240, which is the monochrome (cheaper) version of their portable of the
> mid-late '80's. I found any number of incomplete LA's. Mostly, the pods
> and the sample boards were partly or completely missing. Documentation was
> not common, and, though I found some pods for sale, they were not complete,
> and none I was offered had documentation. Unfortunately, it's too easy to
> develop excessive or erroneous expectations of what the instrument will do
> if you don't have doc's so you'd better have them. I found several
> 1240/41's for <$250, but those were without pods, several were without the
> required sample boards, and none had documentation. I found pods, often
> costing more than $250 for a pair, again without documentation and, worse,
> without the lead sets and probe clips that you need to attach to a device

  I've looked at the Tek 1240/1241...both seemed pretty nice. From my
sources, though, they get awfully expensive (>$800) if they're complete
with lots of options, pods, clips, and docs.

> Before you buy, be ceratin that YOUR preferred triggering methods are
> supported. I've found triggering the most critical problem of logic
> analyzer application, and if there's even a single conceivable mode that
> isn't supported, THAT's the one you'll need, ... trust me.

  Sounds good to me. Thanks for the advice!

       -Dave McGuire
Received on Sun Dec 31 2000 - 14:57:07 GMT