Re: Oscilloscope Sale at Tech America

On Tue, 3 Mar 1998 15:22:10 -0500 (EST), Mitchell Rohde <bovine@eecs.umich.edu>
wrote:

>
>> sweep speed is 0.2msec/Div. Includes 2 probes (X10, X1) 90 day limited
>> warranty.
>
> I would be leary of such an item. Two reasons stand out:
>
> 1) It has lots of features. It is better, IMHO, to have a solid scope
>that supports basic functions very well than a whole bunch of cheezy
>extras that all sort-of kind-of half work. Look at meters. You can get a
>digital meter for $30 that has all the features of a $200 Fluke... but it
>is unlikely that the performance and longevity will compare.
>
> Some things I wouldn't say this for, but real, good tools are worth every penny.
>
> 2) A 90 day limited warranty? Sounds pretty weak. If it were a 1 year
>total warranty I would not suspect... but 90 days? What is this, let's
>make a deal?

True on both cases, but you also have to consider that $30 digital meters of
today are more accurate than $3000 tube based Tektronic meters of the 60's.

Technology has come along way with "voltmeters on a chip" making for some very
cheap equipment than works relatively well. The differences between Fluke and
Protek meters today are more a difference in housing construction, and
calibration than hardware design. The Fluke is going to be better calibrated,
and will handle a fall from a bench better. But if the Protek says you have
2.5v on a 5v power supply, you might really have 2.495 volts, but either way it
ain't 5v.

The calibration of the Protek is not going to match that of a Fluke. And 20mhz
limits it's usefulness in many other fields, but is plenty for Arcade repair
(and most audio apps for that matter). But hell $250? Dual trace with X/Y/Z
modes? Not bad. I've used Protek scopes in the past, they don't explode or
anything when you turn them on -- and the one I was using was well over 90days
old.

You won't go wrong buying a Tektronics or Fluke scope, if you can afford it.
But to fix an old X/Y Arcade game you don't need a 250mhz Tektronics scope. You
just need to see a low frequency waveform being displayed. If the waveform's
not right it won't matter if the voltage of the waveform displayed is off by
0.5%

As far as extra features, those are freebies because of newer technology.
Having "features" is not a bad thing. My TV has Picture in Picture, all
adjustments (Contrast, Volume, etc) can be made from across the room. It can
wake me in the morning, turn itself off at night, and automatically search the
spectrum for valid channels, allowing me to lock out QVC. It cost about the
same as my Dad paid for a living room TV that we had to get up and twist a
mechanical knob to "kerchunk" between channels.

Those options are most likely built into the "Scope on a Chip" that the IC
designers threw in to sell more "Scope on a Chip" ICs.

What do I own? A 250mhz Tektronics scope I paid $600 for used. And a 4 1/2
Fluke meter that I got instead of payment from a company going bankrupt. -- Like
I said, you won't go wrong with Tektronics and a Fluke! ;^)

-Zonn

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Received on Tue Mar 3 13:45:21 1998