Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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  #1   Report Post  
tempus fugit
 
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Default opinions on buying a scope

Hey all;

I'm thinking about adding a couple things to my test equipment arsenal, and
I was thinking about a scope. I've seen quite a few on eBay going fairly
cheap, but I'm not sure what I need for capability (or even if I really need
a scope) My main diagnostic tool is a DMM. I mostly work with audio stuff
(built and designed few things) and the odd repair for a family member of
some piece of consumer gear, so I don't need anything too intense I don't
think. What kind of bandwidth is useful? I'm guessing there are some older
scopes out there with such limited bandwidth as to be useless anymore (maybe
that's why they're so cheap). What about a PC scope (hardware or soft -
although I suppose the software type will be limited to 20kHz bandwidth).
Can anyone point me to a good tutorial site on how to use a scope,
applications, tricks, etc?

Thanks




  #2   Report Post  
Razor's Edge
 
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You make me all confused, you say you built and designed a couple of audio
stuff.... hmm. without an o-scope???

That's the FIRST thing you need to see the results of your *audio* projects,
my friend!

I don't think you'll need anything better than a simple 2channel 20MHZ
scope...

Cheers
Stefan




"tempus fugit" skrev i meddelandet
...
Hey all;

I'm thinking about adding a couple things to my test equipment arsenal,

and
I was thinking about a scope. I've seen quite a few on eBay going fairly
cheap, but I'm not sure what I need for capability (or even if I really

need
a scope) My main diagnostic tool is a DMM. I mostly work with audio stuff
(built and designed few things) and the odd repair for a family member of
some piece of consumer gear, so I don't need anything too intense I don't
think. What kind of bandwidth is useful? I'm guessing there are some older
scopes out there with such limited bandwidth as to be useless anymore

(maybe
that's why they're so cheap). What about a PC scope (hardware or soft -
although I suppose the software type will be limited to 20kHz bandwidth).
Can anyone point me to a good tutorial site on how to use a scope,
applications, tricks, etc?

Thanks







  #3   Report Post  
Patch
 
Posts: n/a
Default opinions on buying a scope


"tempus fugit" wrote in message
...
Hey all;

I'm thinking about adding a couple things to my test equipment arsenal,

and
I was thinking about a scope. I've seen quite a few on eBay going fairly
cheap, but I'm not sure what I need for capability (or even if I really

need
a scope) My main diagnostic tool is a DMM. I mostly work with audio stuff
(built and designed few things) and the odd repair for a family member of
some piece of consumer gear, so I don't need anything too intense I don't
think. What kind of bandwidth is useful? I'm guessing there are some older
scopes out there with such limited bandwidth as to be useless anymore

(maybe
that's why they're so cheap). What about a PC scope (hardware or soft -
although I suppose the software type will be limited to 20kHz bandwidth).
Can anyone point me to a good tutorial site on how to use a scope,
applications, tricks, etc?

Thanks

If all you're going to do is audio work, the cheapest scope you can find

would work just fine. My first scope (in 1956) only had a 5 Mhz bandwidth.
My present scope is a dual channel, 100 Mhz. The old 5 Mhz would be a good
one for audio. I've had no experience with the PC scope, but it would be
worth a try.




  #4   Report Post  
Charles Schuler
 
Posts: n/a
Default opinions on buying a scope


"tempus fugit" wrote in message
...
Hey all;

I'm thinking about adding a couple things to my test equipment arsenal,

and
I was thinking about a scope. I've seen quite a few on eBay going fairly
cheap, but I'm not sure what I need for capability (or even if I really

need
a scope) My main diagnostic tool is a DMM. I mostly work with audio stuff
(built and designed few things) and the odd repair for a family member of
some piece of consumer gear, so I don't need anything too intense I don't
think. What kind of bandwidth is useful? I'm guessing there are some older
scopes out there with such limited bandwidth as to be useless anymore

(maybe
that's why they're so cheap). What about a PC scope (hardware or soft -
although I suppose the software type will be limited to 20kHz bandwidth).
Can anyone point me to a good tutorial site on how to use a scope,
applications, tricks, etc?


There is so much stuff on scopes that you will find too much. Here is one
example: http://www.qsl.net/wd1v/scopefaq/index.html
Tektronix, Agilent, and others have some really good stuff in the way of
tutorials and application notes.

For me, a scope is the best instrument in the lab. In fact, if I can have
only instrument, it's going to be a scope.

Others do nicely with other test equipment. I suppose it's a matter of what
one is used to and how one visualizes circuit operation.

As to a used scope, there are some great buys out there. The problem is
getting parts. Many scopes use proprietary ICs that cannot be purchased. I
know people who buy two (or more) of the same model and use one for parts.
Good luck.


  #5   Report Post  
lcoe
 
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Default opinions on buying a scope

Charles Schuler wrote:

"tempus fugit" wrote in message
...
Hey all;

I'm thinking about adding a couple things to my test equipment arsenal,

and
I was thinking about a scope. I've seen quite a few on eBay going fairly
cheap, but I'm not sure what I need for capability (or even if I really

need
a scope) My main diagnostic tool is a DMM. I mostly work with audio stuff
(built and designed few things) and the odd repair for a family member of
some piece of consumer gear, so I don't need anything too intense I don't
think. What kind of bandwidth is useful? I'm guessing there are some older

[....]
There is so much stuff on scopes that you will find too much. Here is one
example: http://www.qsl.net/wd1v/scopefaq/index.html
Tektronix, Agilent, and others have some really good stuff in the way of
tutorials and application notes.


For me, a scope is the best instrument in the lab. In fact, if I can have
only instrument, it's going to be a scope.


as a computer Field Engineer, until just the last few years a scope was
absolutely required, you could get by w/o a meter but not a scope and
a flashlight.

Others do nicely with other test equipment. I suppose it's a matter of what
one is used to and how one visualizes circuit operation.


i like the ones that can give dvm readouts on the crt, pricy i suppose, but
you s/b able to find a used scope with the integral dvm.

As to a used scope, there are some great buys out there. The problem is
getting parts. Many scopes use proprietary ICs that cannot be purchased. I
know people who buy two (or more) of the same model and use one for parts.
Good luck.


my opinion is that if you don't need 150-300mhz or higher, stay away from
well used "pro" units that go cheap (like a Tek 465) w/o a manual and unknown
hours of use. if that puppy goes TU, you are screwed, it just became a boat
anchor (it will weight about that much, too). used "consumer/technician"
scopes are getting more common and may sell for about the same price as
the super duper pro model but it likely is nearly in NEW condition, s/b
much more reliable, and will weight 1/4 as much. i have a dual trace 40mhz
Hitachi, paid 600+shipping in 1987 or so, it will last me another 30 years,
but would only bring (these days) $100-200 in the DFW area.

good luck, --Loren



  #6   Report Post  
tempus fugit
 
Posts: n/a
Default opinions on buying a scope

Thanks for your reply Charles.

The problem is
getting parts. Many scopes use proprietary ICs that cannot be purchased.

I
know people who buy two (or more) of the same model and use one for parts.
Good luck.


So do scopes often fail?


"Charles Schuler" wrote in message
...

"tempus fugit" wrote in message
...
Hey all;

I'm thinking about adding a couple things to my test equipment arsenal,

and
I was thinking about a scope. I've seen quite a few on eBay going fairly
cheap, but I'm not sure what I need for capability (or even if I really

need
a scope) My main diagnostic tool is a DMM. I mostly work with audio

stuff
(built and designed few things) and the odd repair for a family member

of
some piece of consumer gear, so I don't need anything too intense I

don't
think. What kind of bandwidth is useful? I'm guessing there are some

older
scopes out there with such limited bandwidth as to be useless anymore

(maybe
that's why they're so cheap). What about a PC scope (hardware or soft -
although I suppose the software type will be limited to 20kHz

bandwidth).
Can anyone point me to a good tutorial site on how to use a scope,
applications, tricks, etc?


There is so much stuff on scopes that you will find too much. Here is one
example: http://www.qsl.net/wd1v/scopefaq/index.html
Tektronix, Agilent, and others have some really good stuff in the way of
tutorials and application notes.

For me, a scope is the best instrument in the lab. In fact, if I can have
only instrument, it's going to be a scope.

Others do nicely with other test equipment. I suppose it's a matter of

what
one is used to and how one visualizes circuit operation.

As to a used scope, there are some great buys out there. The problem is
getting parts. Many scopes use proprietary ICs that cannot be purchased.

I
know people who buy two (or more) of the same model and use one for parts.
Good luck.




  #7   Report Post  
Charles Schuler
 
Posts: n/a
Default opinions on buying a scope


"tempus fugit" wrote in message
...
Thanks for your reply Charles.

The problem is
getting parts. Many scopes use proprietary ICs that cannot be

purchased.
I
know people who buy two (or more) of the same model and use one for

parts.
Good luck.


So do scopes often fail?


The ones from companies like Tektronix are generally reliable. However,
used ones can have a lot of miles on them and might have been subjected to
harsh environments and abuse by users. We had (where I used to work) dozens
of Tektronix scopes and about a dozen Hitachis. They generally held up well
but there were a few problems. You know how it is with electronic
equipment. Ten people will swear by brand X and then one will come along
and bad mouth that same brand.

You might consider an inexpensive, used scope that you can return if it does
not work. If you find that you really like using it, then it might be time
to invest in a better one.

I have seen some nice buys at hamfests. Are there any in your area? The
vendors are often locals who will be less likely to screw you.

I'd bet that if you are serious about amplifiers and electronics that you
will quickly become a scope fan. A picture is worth a thousand meter
readings!


  #8   Report Post  
Jim Yanik
 
Posts: n/a
Default opinions on buying a scope

"Charles Schuler" wrote in
:


"tempus fugit" wrote in message
...
Hey all;

I'm thinking about adding a couple things to my test equipment
arsenal,

and
I was thinking about a scope. I've seen quite a few on eBay going
fairly cheap, but I'm not sure what I need for capability (or even if
I really

need
a scope) My main diagnostic tool is a DMM. I mostly work with audio
stuff (built and designed few things) and the odd repair for a family
member of some piece of consumer gear, so I don't need anything too
intense I don't think. What kind of bandwidth is useful? I'm guessing
there are some older scopes out there with such limited bandwidth as
to be useless anymore

(maybe
that's why they're so cheap). What about a PC scope (hardware or soft
- although I suppose the software type will be limited to 20kHz
bandwidth). Can anyone point me to a good tutorial site on how to use
a scope, applications, tricks, etc?


There is so much stuff on scopes that you will find too much. Here is
one example: http://www.qsl.net/wd1v/scopefaq/index.html
Tektronix, Agilent, and others have some really good stuff in the way
of tutorials and application notes.

For me, a scope is the best instrument in the lab. In fact, if I can
have only instrument, it's going to be a scope.

Others do nicely with other test equipment. I suppose it's a matter
of what one is used to and how one visualizes circuit operation.

As to a used scope, there are some great buys out there. The problem
is getting parts. Many scopes use proprietary ICs that cannot be
purchased. I know people who buy two (or more) of the same model and
use one for parts. Good luck.



FYI,for a hobbyist who wants a low cost used TEK scope that uses NO custom
ICs,the TEK T922/932/935 (or the TEK 442) are nice scopes that are
relatively new.BW of 15-35 Mhz.Easy to work on.

TEK 422 is an older scope that I have good regard for,too,15 Mhz.
TEK 453,50 Mhz,IIRC.
TEK 454,150Mhz IIRC.

Avoid 200 and 300 series TEK scopes,IMO.

--
Jim Yanik,NRA member
remove null to contact me
  #9   Report Post  
Jim Yanik
 
Posts: n/a
Default opinions on buying a scope


"tempus fugit" wrote in message


So do scopes often fail?


The older scopes have electrolytic caps that fail,switches/pots that get
dirty or noisy.

--
Jim Yanik,NRA member
remove null to contact me
  #10   Report Post  
Uns Lider
 
Posts: n/a
Default opinions on buying a scope

In article , Jim Yanik wrote:
FYI,for a hobbyist who wants a low cost used TEK scope that uses NO custom
ICs,the TEK T922/932/935 (or the TEK 442) are nice scopes that are
relatively new.BW of 15-35 Mhz.Easy to work on.

TEK 422 is an older scope that I have good regard for,too,15 Mhz.
TEK 453,50 Mhz,IIRC.
TEK 454,150Mhz IIRC.


How does the 454 compare to the 475?

-- uns


  #11   Report Post  
tempus fugit
 
Posts: n/a
Default opinions on buying a scope


Avoid 200 and 300 series TEK scopes,IMO.



Do you also mean to avoid 2000 and 3000 series scopes? I see a few of those
on eBay.


Thanks




  #12   Report Post  
tempus fugit
 
Posts: n/a
Default opinions on buying a scope

What about other brands like Hitachi and B&K Precision?


"Jim Yanik" wrote in message
.. .
"Charles Schuler" wrote in
:


"tempus fugit" wrote in message
...
Hey all;

I'm thinking about adding a couple things to my test equipment
arsenal,

and
I was thinking about a scope. I've seen quite a few on eBay going
fairly cheap, but I'm not sure what I need for capability (or even if
I really

need
a scope) My main diagnostic tool is a DMM. I mostly work with audio
stuff (built and designed few things) and the odd repair for a family
member of some piece of consumer gear, so I don't need anything too
intense I don't think. What kind of bandwidth is useful? I'm guessing
there are some older scopes out there with such limited bandwidth as
to be useless anymore

(maybe
that's why they're so cheap). What about a PC scope (hardware or soft
- although I suppose the software type will be limited to 20kHz
bandwidth). Can anyone point me to a good tutorial site on how to use
a scope, applications, tricks, etc?


There is so much stuff on scopes that you will find too much. Here is
one example: http://www.qsl.net/wd1v/scopefaq/index.html
Tektronix, Agilent, and others have some really good stuff in the way
of tutorials and application notes.

For me, a scope is the best instrument in the lab. In fact, if I can
have only instrument, it's going to be a scope.

Others do nicely with other test equipment. I suppose it's a matter
of what one is used to and how one visualizes circuit operation.

As to a used scope, there are some great buys out there. The problem
is getting parts. Many scopes use proprietary ICs that cannot be
purchased. I know people who buy two (or more) of the same model and
use one for parts. Good luck.



FYI,for a hobbyist who wants a low cost used TEK scope that uses NO custom
ICs,the TEK T922/932/935 (or the TEK 442) are nice scopes that are
relatively new.BW of 15-35 Mhz.Easy to work on.

TEK 422 is an older scope that I have good regard for,too,15 Mhz.
TEK 453,50 Mhz,IIRC.
TEK 454,150Mhz IIRC.

Avoid 200 and 300 series TEK scopes,IMO.

--
Jim Yanik,NRA member
remove null to contact me



  #13   Report Post  
Loren Coe
 
Posts: n/a
Default opinions on buying a scope

In article , Uns Lider wrote:
In article , Jim Yanik wrote:
FYI,for a hobbyist who wants a low cost used TEK scope that uses NO custom
ICs,the TEK T922/932/935 (or the TEK 442) are nice scopes that are
relatively new.BW of 15-35 Mhz.Easy to work on.

TEK 422 is an older scope that I have good regard for,too,15 Mhz.
TEK 453,50 Mhz,IIRC.
TEK 454,150Mhz IIRC.


How does the 454 compare to the 475? -- uns


iirc, these are different generations, both dual trace "Field"
scopes. the 475 was the least favored of the three in that
series, more expensive/less reliable than the 465, and way
lower performance that the topline 485. the 485 was considered
the best in class and was reliable. all had delayed sweep.

these all are very old, 40yrs? so caveate emptor. --Loren


  #14   Report Post  
Jim Yanik
 
Posts: n/a
Default opinions on buying a scope

Loren Coe wrote in
news:KFrUa.132758$GL4.34318@rwcrnsc53:

In article , Uns
Lider wrote:
In article , Jim Yanik
wrote:
FYI,for a hobbyist who wants a low cost used TEK scope that uses NO
custom ICs,the TEK T922/932/935 (or the TEK 442) are nice scopes
that are relatively new.BW of 15-35 Mhz.Easy to work on.

TEK 422 is an older scope that I have good regard for,too,15 Mhz.
TEK 453,50 Mhz,IIRC.
TEK 454,150Mhz IIRC.


How does the 454 compare to the 475? -- uns


iirc, these are different generations, both dual trace "Field"
scopes. the 475 was the least favored of the three in that
series, more expensive/less reliable than the 465, and way
lower performance that the topline 485. the 485 was considered
the best in class and was reliable. all had delayed sweep.

these all are very old, 40yrs? so caveate emptor. --Loren




485 has a complex switching power supply that is a tough one to repair,the
scope uses more TEK-made IC's than any other 400 series portable.

454 was a good scope,but is a generation behind the 475.
454 has no TEK-made ICs,475 has several;in the vertical,trigger,and sweep
circuits.

TEK-made IC's are no longer made,no longer available from TEK.Only from
cannabalized scopes or perhaps some folks (other than TEK-US) still have
some stock of new ICs in their bench stock or toolbox.( a real long shot!)

--
Jim Yanik,NRA member
remove null to contact me
  #15   Report Post  
Jim Yanik
 
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"tempus fugit" wrote in
:

What about other brands like Hitachi and B&K Precision?


I have no knowledge,experience with,or opinions of any of them.



--
Jim Yanik,NRA member
remove null to contact me


  #16   Report Post  
lcoe
 
Posts: n/a
Default opinions on buying a scope

Jim Yanik wrote:
"tempus fugit" wrote in
:


What about other brands like Hitachi and B&K Precision?
I have no knowledge,experience with,or opinions of any of them.


Hitachi is good, imho, i own a 35mhz dual trace, new in 1985 or
so. nice sw's and has "uncal" led/s. unusual for a 600.00 scope.

manual has shematics and it is light-weight (14lbs?). --Loren




--
Jim Yanik,NRA member
remove null to contact me

  #17   Report Post  
tempus fugit
 
Posts: n/a
Default opinions on buying a scope

I think the 465 is not a dual trace scope (correct me if I'm wrong). How
important is it to have the dual trace? Also, is it important that the scope
be calibrated when I buy it, or is this fairly easy to do on your own?

Thanks


"Jim Adney" wrote in message
...
On Sat, 26 Jul 2003 09:16:27 GMT Loren Coe
wrote:

iirc, these are different generations, both dual trace "Field"
scopes. the 475 was the least favored of the three in that
series, more expensive/less reliable than the 465, and way
lower performance that the topline 485. the 485 was considered
the best in class and was reliable. all had delayed sweep.

these all are very old, 40yrs? so caveate emptor.


The 453 (60MHz) and 454 (150MHz) came out in the late 60s.

The 465 (100MHz), 475 (200MHz), 475A (250MHz) and 485 (350MHz) all
came out in the 70s, if not in 1970. These have somewhat larger
displays than the 45x scopes.

The 465B (100MHz) came out in ~1980 as a replacement for the 465. The
other models continued for another ~10 years. The 465/465Bs were some
of Teks most popular scopes ever. They would be my first choice for a
used Tek scope except that I already have one.

The 485 was really not in the same family. It was physically larger
and more complicated and had a completely different power supply that
is difficult to troubleshoot.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------



  #18   Report Post  
Jim Yanik
 
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lcoe wrote in
news:%dkVa.2020$uu5.525@sccrnsc04:

tempus fugit wrote:
I think the 465 is not a dual trace scope (correct me if I'm wrong).
How


wrong. it certainly is.

important is it to have the dual trace? Also, is it important that
the scope


well, if you want to compare timing or look at more than a single
signal, it is almost essential. lot's of lab scopes went to 4 trace
long, long, ago.

be calibrated when I buy it, or is this fairly easy to do on your
own? Thanks


that, i dunno. if you are making a living with the thing, better get
it calibrated. otherwise, find some known frequency and calulate it
for yourself. 60hz power is the only common that i have used. there
s/b others, tho, maybe in tv's? --Loren



there's more to calibration than just checking the time-base(especially at
ONE range). Attenuator compensation can change,freq.response,trigger
sensitivity and DC trigger levels.Attenuators can also go out of
tolerance;voltage inaccuracy.I've seen where only a few timing ranges were
in error,too.

--
Jim Yanik,NRA member
remove null to contact me
  #19   Report Post  
Jim Yanik
 
Posts: n/a
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"tempus fugit" wrote in
:

I think the 465 is not a dual trace scope (correct me if I'm wrong).
How important is it to have the dual trace? Also, is it important that
the scope be calibrated when I buy it, or is this fairly easy to do on
your own?

Thanks




For a proper calibration,you need a known timing standard;with time marks
from 5 sec to 10ns,a variable amplitude sq.wave generator,up to 60Vp-
p/100Khz,an amplitude calibrator.The 465 service manual lists suggested
calibration equipment,at the beginning of the cal procedure.(just checking
with 60 hz line freq is not going to do it.)

It's not hard at all if you have the right equipment. 8-)

--
Jim Yanik,NRA member
remove null to contact me
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