Oscilloscope

[Peter9DO]

Re: Oscilloscope

WOW! I can't believe how many modules they made for these! Now that's crazy!

[Peter9DO]

Re: Oscilloscope

Thank you for all the information! Trying to pick out a scope has proven itself to be much more annoying than it should have been! I really do think my budget has a lot to do with it. I know I should think about moving the budget up some but I just don't know how frequently I will use the scope so I really don't want to pay a lot of money for it. Well I have been going back and forth with a gentleman regarding a Tek 2220 which has a digital storage on it (going off of your advice about the digital storage) although it's only 60MHz. The guy wants a little to much for it though at $250 with no probes, I have found this same scope on eBay in the $150 area. I'm going to see if he will come down in price some.

All in all, how do you feel about the Tek 2220? As I said I normally work on laptops but am venturing out and have been doing work on LCD TVs and plasmas as well. All the service manuals claim that a oscilloscope is needed to test waves. Also, would I need a function generator for what I'm trying to do?

[PCBONEZ]

Re: Oscilloscope

I really don't understand the whole MHz even
after a whole night of watching oscilloscope videos

Sorry, I didn't see that before.
The MHz is the Bandwidth.
The scope's bandwidth should be at least three times the bandwidth of the signal to be measured.
In other words a 50MHz scope is good for measured frequencies less than about 16 MHz.
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Also want a sample rate around 10 times the bandwidth.
For a 50 MHz scope that would be at least 500 MS/sec [or 0.5 GS/sec]
- This is so there are enough 'dots' for the scope to figure out an accurate wave form to display.
[Think like connecting dots on graph paper to make a curve. The samples are the dots.]
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A 50MHz scope is fine for measuring ripple [around 50k-300k Hz] but if you ever need to check MOSFETs for ringing it might not be good enough. That can be up in the MHz range [say 10 MHz+] and you really need at least a 1 GS/sec sample rate to be sure of getting a good trace.
Indirectly that means you need a 100MHz scope.
[There could be odd-ball 50MHz scopes with a 1GS/sec Sample Rate that would work but 'Bandwidth x10 = Sample Rate' is the norm, at least with older scopes.]
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The above is general, ball-park, rule of thumb and opinion.
Not everyone is going to agree.
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[PCBONEZ]

Re: Oscilloscope

Mine is a Tektronix 7633.
Probably out of your price range but you never know... Sh*t happens..
The Tektronix 7000 series are 'frame' type.
Those 3 modules [aka "Plug-ins"] you see under the screen slide out and are interchangeable with others to reconfigure it into various kinds of scopes.
There is even a plug-in to turn it into a spectrum analyzer. [No I don't have that.. LOL]
I do have 7 various modules for it though.
It's 100MHz but there's are modules that upgrade to like 400 or 500 MHz. [I forget because I don't need one.]
There is actually a 1GHz module for the series but I don't think my frame version is compatible with that one.
This guy is an old TEK nut.
http://www.barrytech.com/tektronix/t...000scopes.html
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Mine doesn't have a way to display on a PC if that matters to you.
There were some that did back then but AFAIK they required an ISA card for the interface so you'd have to throw together a vintage PC just for that purpose.
The interface was called GPIB.
For GPIB you need a scope with a GPIB-out, an add-in PC card with a GPIB-in, a GPIB cable, and the GPIB software.
GPIB to USB converters exist but they are rare and usually expensive.
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The Tek 5000 series - too old, don't go there. - Those still had tubes.
Unless of course you LIKE tubes... LOL.
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The Tek 2000 series is a good one for you to look for.
They did have DSO and/or Storage versions.
To check if it's analog or not use google and check in a few places because sometimes the sites are wrong.

The Tektronix 4xx models were also good and came with memory versions but 'light weight' isn't a good description of those.
http://www.ebay.com/itm/220918982982
Those were the most common scope in the Navy in the 80's and 90's.
I've used lots of them. - A little old now but not too bad for a scope.
They are pretty darned rugged as scopes go.
Have to be to get hauled up and down ladders to the work site all the time.

The Tek 2000 series are newer and lighter than the 4xx Series.
Still fairly rugged.
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There are a number of other good brands but finding documentation might be more difficult.
Always check that before you buy.
And DON'T buy a completely 'untested' scope.
- If it at least shows a signal with an input you can probably adjust it in good enough.
Also beware of weak picture tubes. They aren't so cheap.
And, watch out for busted/bent knobs. Common with scopes. Sometimes cheap to fix other times not.
Ideally you want to find the actual service manual before you buy it.
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Were I you I'd save up until you have $400 to throw at this.
Can probably score a 100MHz that's calibrated and/or has a warranty for that much.
In the long run you'll probably be better off.
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Someone [here, another thread] tried an Owon w/LCD screen in 60MHz [I think] and it was at least okay for checking ripple from PSUs.
[edit] er... Maybe it was an Owon knock-off. At any rate it was an LCD screen w/USB and it looked like an Owon... LOL.
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I tried a USB powered Hantek myself and I thought it sucked.
The noise [ripple] in the PC's USB port [meaning the scope's power source] ended up on the screen mixed into the the actual signal.
Kind of hard to measure ripple when you already have ripple on the screen with the probe disconnected.
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[Peter9DO]

Re: Oscilloscope

By the way what model number is the one you have?

[Peter9DO]

Re: Oscilloscope

Oh..... Yea, see if you put DSO scope in you will see the items I'm talking about. It almost looks like the back of a camera. A small portable oscilloscope, with maybe a 3" screen. It looks very cheap and I thought that's what you were talking about.

In the last few days I have someone that I have been in contact with regarding a Tektronix Model 2225. I don't think this has a digital storage and it's only 50MHz. I really don't understand the whole MHz even after a whole night of watching oscilloscope videos

[PCBONEZ]

Re: Oscilloscope

Now just so we are on the same page, when you say DSO your are referring to the Nano style oscilloscopes correct?

No.
DSO stands for Digital Storage Oscilloscope.
It's a standard term.
All it means is the scope has some memory in it so it can save a trace and display it for as long as you want to look at it.
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Analog scopes don't do that.
They display in real time, then it's just gone.
Very hard to trouble shoot intermittent problems [spikes] or see the shape of a pulse with an Analog scope.
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I don't even know what you mean by a Nano style scope.
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My DSO was made in the 80's so they call it a 'Storage' scope even though it's an actual DSO.
It looks like this:
.

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[Peter9DO]

Re: Oscilloscope

-Comparatively- Analog scopes aren't good for much.
With Analog each trace passes and then goes *poof*.
There is no memory to keep the trace in the machine.
They are intended for signals that are exactly the same on every pass which isn't useful to find spikes in ripple or things like that.
With DSO's you can hold a single trace on the screen so you can actually look at it for a bit. That's why when the were introduced they were called 'memory' or 'storage' o'scopes.
There was an intermediate kind of scope [and advanced analog so to speak] where the phosphor on the tube would glow for longer than normal so you could actually look at it for a short time but I don't think those have been made since the 70's or early 80's.
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No, DSO aren't low MHz. That is a ridiculous statement.
They go way up into the GHz range now days.
My Tektronix is like 30 years and it came in a 1Ghz version way back then.
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If you're planning on buying new and want a decent scope you need to rethink your budget because that's your problem.
Buying new you aren't going to get much of a scope for $200.
A used 100 Mhz DSO shouldn't be too hard to find for $200.
For new then you need to think more like $300-$400 and look for an el'cheapo Chinesse brand.
.

I never said I was looking for a new oscilloscope, I can care less if its new or used, I just want a working one. As for my budget of $200, unfortunately it is what it is, with a child on the way there really is nothing more I would be willing to do for a piece of equipment that I don't know how much it will come of use to me. Now just so we are on the same page, when you say DSO your are referring to the Nano style oscilloscopes correct? If that's the case I really have not seen any over 25MHz, that were reasonable priced, and this is why I have made that statement. If this is not what you mean by DSO, then I really don't know what your talking about then and if you would be willing to enlighten me some.

Thank you,
Peter

[PCBONEZ]

Re: Oscilloscope

I have done a lot of reading about the DSOs and I have not seen to many people that like them. Also, they are very low MHz (at least the ones in my budget).

-Comparatively- Analog scopes aren't good for much.
With Analog each trace passes and then goes *poof*.
There is no memory to keep the trace in the machine.
They are intended for signals that are exactly the same on every pass which isn't useful to find spikes in ripple or things like that.
With DSO's you can hold a single trace on the screen so you can actually look at it for a bit. That's why when the were introduced they were called 'memory' or 'storage' o'scopes.
There was an intermediate kind of scope [and advanced analog so to speak] where the phosphor on the tube would glow for longer than normal so you could actually look at it for a short time but I don't think those have been made since the 70's or early 80's.
.
No, DSO aren't low MHz. That is a ridiculous statement.
They go way up into the GHz range now days.
My Tektronix is like 30 years and it came in a 1Ghz version way back then.
.
If you're planning on buying new and want a decent scope you need to rethink your budget because that's your problem.
Buying new you aren't going to get much of a scope for $200.
A used 100 Mhz DSO shouldn't be too hard to find for $200.
For new then you need to think more like $300-$400 and look for an el'cheapo Chinesse brand.
.

[Th3_uN1Qu3]

Re: Oscilloscope

If it were me i would pick the Rigol. A lot of enthusiasts have it (just check the EEVBlog forums) so if you need help on using it, or if something goes wrong, you'll always get quick answers.

[Peter9DO]

Re: Oscilloscope

If you are repairing plasmas to make money, it may be a very difficult resale market. Prices keep dropping every year for new plasmas.

On boxing day, one store had limited quantities of a Samsung 43 inch 720p plasma for $299 Canadian.

50inch 720p plasmas are around $500 now.

Yea, I know they are killing me with these prices. I will continue to say it I have much, much, much better luck with LCDs than plasmas. I have 3 - 42" sitting here that I have paid nothing for, or close to nothing for, so if I can repair them for under $100 and even sell it for $150 I would be happy! Also you have to keep in mind that the sales that the big companies put out are always limited quantities and it's normally for a day. Where if you can offer low prices all year round people love it!

I'm pretty successful in my other ventures such as laptops, iPods and monitors. It's always good to have a background in a variety of different products to hit different markets. If you have the ability to purchase a broken plasma for $20 or even for just getting it out of someones house it's worth giving it a shot to repair it, wouldn't you agree?

[retiredcaps]

Re: Oscilloscope

From what a lot of people are saying is that Owon is nothing but garbage.

I don't have a scope and don't plan to get one so I can't give an informed opinion regarding brands.

I'm just good at watching the videos and trying to learn something!!

[Peter9DO]

Re: Oscilloscope

I also like afrotechmods' videos (10 minutes total for all 3). I believe he is Canadian.

Oscilloscope Tutorial Part 1 - Choosing an oscilloscope

http://www.youtube.com/watch?v=qIfo_-d82Co

Part 2

http://www.youtube.com/watch?v=hUIgAu3QQWQ

Part 3

http://www.youtube.com/watch?v=g_KuGEh0PyA

Well I like the oscilloscope he has, it's a little out of budget but I would spend the little extra cash for one like this. Now that I have looked at the reviews on it, everyone says it's a piece of junk. I think the only people that have said something positive about it is the people that have pictures of them taking it out of the packaging posted! lol! From what a lot of people are saying is that Owon is nothing but garbage. Again, I'm just going off what the majority of people have posted about the product.

Also in this guys first video he said the best ones are HP, Tektronix and HP/Aqulent. Then he is showing off his Owon, what's that all about? lol! His videos were great though, I have seen the 1st and 2nd one before, but I did watch them again, just to refresh the memory.

[retiredcaps]

Re: Oscilloscope

If you are repairing plasmas to make money, it may be a very difficult resale market. Prices keep dropping every year for new plasmas.

On boxing day, one store had limited quantities of a Samsung 43 inch 720p plasma for $299 Canadian.

50inch 720p plasmas are around $500 now.

[Peter9DO]

Re: Oscilloscope

A 100 MHz (or greater) 'memory' or 'DSO' scope is the way to go if you only have one.
Much more useful than an analog scope.
.
If it doesn't come with a manual then check the availability of the manual before you commit to buying the scope in question.
.

I have done a lot of reading about the DSOs and I have not seen to many people that like them. Also, they are very low MHz (at least the ones in my budget). They do look nice and the little room that it would take up on my work bench is most definitely a plus, but I think it's just out of my price range. Do you know of any DSO that's 100MHz and under $200?

Then for the USB ones they also fall under the very convenient but expensive category for me. If they have decent specs they are out of this world expensive. This was actually one of the first type that I looked into because it really was not going to take up any room on my work bench and I have a monitor mounted on the wall right in front of the bench as well so it would have been perfect! I came across a decent one for $199 that had me thinking but when I started reading reviews on it, I had to move on. I don't remember the make or model off hand, but if I can come across it I will post it to see if anyone else has used this scope.

Thank you for your reply!!!!!

[Peter9DO]

Re: Oscilloscope

You're correct about that Plasmas and LCDs for that matter normally require the entire board replaced rather than just being repaired. However with plasma TVs even in the manufacture's service manuals it shows the need of an oscilloscope for measuring wavelengths and such. In the past I have had great success with just using my multimeter, mainly on LCDs. However Plasma TVs seem to be a different beast. I have had no luck on plasmas. I just don't want to be limited to what I can test, it's very frustrating to me when I don't have the proper tools to do a job. I figure with the amount of electronics that I work on that I should have one at my disposal anyways and it would be nice to know how to use it as well. I need to buy as much equipment as I can now before my baby comes in Feb. I won't have the money for this stuff soon! lol!

[retiredcaps]

Re: Oscilloscope

Rigol at $399 that is mentioned

http://www.saelig.com/PSBE100/PSPC017.htm

PS. A lot of TV "repair" is more like replacement especially replacing complete boards in plasmas. Look through some of the threads at Troubleshooting TVs and Video Sources here and you will see what I mean. Very few cases actually require a scope. A standard multimeter is sufficient for 90% of the cases.

[PCBONEZ]

Re: Oscilloscope

A 100 MHz (or greater) 'memory' or 'DSO' scope is the way to go if you only have one.
Much more useful than an analog scope.
.
If it doesn't come with a manual then check the availability of the manual before you commit to buying the scope in question.
.

[retiredcaps]

Re: Oscilloscope

I would like to stay under $200 or right in the area of $200.

I should have mentioned that some of the eevblog videos are well past the $200 mark. You still learn something though.

I think the Rigol scope in some of his videos is $399?

Afrotechmods review is at $329.

http://www.youtube.com/watch?v=KiY9R93XA1g

[shovenose]

Re: Oscilloscope

I don't know a whole lot about Oscilloscopes but as far as I can tell c_hegge likes his Stringray USB one... which is cool because you can screenshot the stuff