Re: oscilloscope.. (fwd)

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Moderated and approved by: Gerry Reynolds <greynolds@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Fri, 22 Dec 2006 18:32:30 -0700
From: Terrell Fritz <terrellfone@xxxxxxxxxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: oscilloscope.. (fwd)

Hi,

At 11:09 PM 12/21/2006, you wrote:

>From: Chip Ford <chipford@xxxxxxxxxxxxxx>
>To: Tesla list <tesla@xxxxxxxxxx>
>Subject: oscilloscope..
>
>I am thinking of purchasing an oscilloscope. There are many out there with 
>many features..10mhz-1ghz. Digital, dual trace, analog..etc. seems that 
>the most common are @ 100 mhz, 2 channel. Most do not include probes. 
>These are not cheap so, If you-all would give me some advice on buying a 
>scope..or if someone has one in working order for sale...let me 
>know..Thanks in advance...Chip Ford

I would get 60 - 100MHz.  Less might be a problem for some things and 
normal people will never need more than 100MHz (but it does not hurt if the 
price is the same).  There are 10 to 60MHz scopes to that are made cheaper, 
but you can get a good Tek off Ebay for less money...  But you can also get 
off brands for like $50...  I have given lower MHz Tek scopes away for free 
before, but I am out of of stock ;o))

Definitely get dual trace.  Rarely would you "want" more unless the price 
is the same...

Good probes are expensive like $75 each and cheap ones are 
"cheap"...  Often though you just have to eat it there since they do wear 
out with much use.  They have all kinds of probes on Ebay now ;-))  Note 
for many things you can just use a BNC cable with alligator clips and tough 
things might need special probes anyway.  But you normally will use 10X 
probes "all the time"...

Tektronix scopes are super ultra good and you can buy older ones for 
pennies on the dollar of what they cost new.  Unless they are already 
broken, they will never break in home use unless you run over them with the 
car (might need a heave truck actually...).  They often run 10 years in 
industry and 30 years just sitting on the shelf...  Don't worry about 
manuals since they can all be downloaded for free or by talking to the 
bridge troll.  But they all run the same so any generic manual or on-line 
class notes are fine if you can't figure it out just be playing with it.

Storage is super nice but it will cost you 10X.  Digital with color LCD 
screen and floppy or USB drive storage will cost a ton more too.  Might as 
well buy them new since theose never sell cheap...

Go to ebay and type in "oscilloscope" and look around.  For a few hundred 
dollars you can get a real nice one.  I am happy to see they sell ones like 
mine for just $200 less than I paid new six years ago :o)))

http://cgi.ebay.com/Tektronix-Digital-Phosphor-Oscilloscope-TDS3012B_W0QQitemZ190064113337QQihZ009QQcategoryZ104247QQrdZ1QQcmdZViewItem

I used to use one of these at work but we paid $17,000 for it:

http://cgi.ebay.com/TEKTRONIX-TDS-520-500MHZ-2-CHANNEL-DIGITAL-OSCILLOSCOPE_W0QQitemZ250063117254QQihZ015QQcategoryZ104247QQrdZ1QQcmdZViewItem

These are a very popular scope so they go for a song despite being one of 
the best ever made:

http://cgi.ebay.com/Tektronix-2235-100-MHz-Used-Oscilloscope_W0QQitemZ150072692730QQihZ005QQcategoryZ104247QQrdZ1QQcmdZViewItem

Inexpensive Tek digitals do show up too:

http://cgi.ebay.com/tektronix-Digital-Oscilloscope-model-1002_W0QQitemZ170062217260QQihZ007QQcategoryZ104247QQrdZ1QQcmdZViewItem

http://cgi.ebay.com/Tektronix-TDS-210-Two-Channel-Digital-Oscilloscope_W0QQitemZ270070171374QQihZ017QQcategoryZ25415QQrdZ1QQcmdZViewItem

Very nice for the money if you can find them.  But the bidding usually goes 
pretty high.

Stay away from battery portable types since the batteries will cost more 
than the scope.  Avoid "vintage" and "rare"...  They have not used tubes 
(other than the picture tube) since the 70's, so don't bother with a tube 
one which would be a pile of trouble.  I would avoid the hand held 
"scopemeter" and boxes the hook to your computer things.  The hand helds 
are expensive for what they do and assume you really know what you are 
doing.  The "turn you computer into a scope" things are more expensive and 
far less capable then an Ebay scope for less money.

In general, any working 100MHz dual trace normal looking Tek scope will 
outperform anything else and will cost less...  It will do more than you 
will probably ever need.  Everyone wants "digital" now so they are 
"dumping" older scopes like mad.

I would avoid "as is - we don't know how to test" since any monkey selling 
oscilloscopes can tell in 60 seconds if it basically works...  Avoid broken 
ones since a single part could cost more than you paid.  You can by several 
broken ones though to make a good scope if you can do things like that.  It 
is very hard to break a good scope, and very bad when they do manage to get 
broken.  Tek service manuals are on-line and many people have gotten super 
good deals on scope that had "easy" problems.  But those folks usually have 
five other scopes already to help fix it ;-))

This one looks really nice:

http://cgi.ebay.com/TEKTRONIX-2465-OSCILLOSCOPE-300MHz-4-CHANNEL-OPTIONS_W0QQitemZ300062270215QQihZ020QQcategoryZ104247QQrdZ1QQcmdZViewItem

I used on of those for years too and they are tough and can do 
everything.  They tend to be pricey for that reason...  But you can always 
sell it for the same.

Never buy one of these since (like a Cadillac) it will be worth about 50 
bucks five years from now:

http://cgi.ebay.com/Tektronix-TDS6604-6-GHz-Digital-Oscilloscope-w-Options_W0QQitemZ270070737241QQihZ017QQcategoryZ104247QQrdZ1QQcmdZViewItem

If you want to pay like a thousand or two, Tektronix has nice lower cost 
all color digitals too.

http://www.tek.com/products/oscilloscopes/tds1000_tds2000/index.html

These store, measure, calculate, talk to computers, do all the work for 
you, etc...  Very useful!!  but you pay more for it.  Usually a "next" 
scope for those that find they can't live without them ;-))

Cheers,

         Terry