Buying an Oscilloscope
1. It's important to keep in mind that a scope is a highly complex piece of electronic test equipment, and not only has to be functional, but correctly calibrated to actually be useful. Many scopes can be broken down into these rough categories:
A. Known bad or broken (Consider it as parts only, or repairable if you are highly skilled with access to parts)
B. Unknown condition and calibration, not shown with a trace (LEAST Desirable as a usable scope)
C. Unknown condition and calibration, but shown with a working trace (Worth considering, especially if you have lab access)
D. Condition known good, shown working (Very desirable, even for those unable to fix it themselves)
E. Known good, provided with calibration and warranty, shown working (Best possible for all buyers)
2. People sell scopes for many reasons, not all of them good for you. The unit many have problems, especially subtle ones, that can't be fixed, or the unit may be in poor condition, damaged or very old. As general rule, buy NO SCOPE unless it is shown working, unless you only intend to buy it for parts. And certainly buy nothing with no picture at all, the classic tell-tale of a disaster in the making. On the positive side, many excellent instruments get sold off as sites downsize or get new equipment, and there are some excellent buys to be had.
...read the full guide with pics here
1. It's important to keep in mind that a scope is a highly complex piece of electronic test equipment, and not only has to be functional, but correctly calibrated to actually be useful. Many scopes can be broken down into these rough categories:
A. Known bad or broken (Consider it as parts only, or repairable if you are highly skilled with access to parts)
B. Unknown condition and calibration, not shown with a trace (LEAST Desirable as a usable scope)
C. Unknown condition and calibration, but shown with a working trace (Worth considering, especially if you have lab access)
D. Condition known good, shown working (Very desirable, even for those unable to fix it themselves)
E. Known good, provided with calibration and warranty, shown working (Best possible for all buyers)
2. People sell scopes for many reasons, not all of them good for you. The unit many have problems, especially subtle ones, that can't be fixed, or the unit may be in poor condition, damaged or very old. As general rule, buy NO SCOPE unless it is shown working, unless you only intend to buy it for parts. And certainly buy nothing with no picture at all, the classic tell-tale of a disaster in the making. On the positive side, many excellent instruments get sold off as sites downsize or get new equipment, and there are some excellent buys to be had.
...read the full guide with pics here
Hi 😀
In every case to purchase an used scope is as a lottery.
Some are almost new and they originate from stores or military equipment.
Others originate from factories that they have used them for testings
= many hours of operation
Others originate from private laboratories and they could have been modified.
My opinion is that it is not worthwhile to purchase used scopes on-line
if it is very expensive. 🙂
In every case to purchase an used scope is as a lottery.
Some are almost new and they originate from stores or military equipment.
Others originate from factories that they have used them for testings
= many hours of operation
Others originate from private laboratories and they could have been modified.
My opinion is that it is not worthwhile to purchase used scopes on-line
if it is very expensive. 🙂
http://www.measuregroup.co.za/index_files/page0149.htm
I found a local company that sells, repairs, recalibrates, and stock secondhand units....
See anything there that might do as a starter scope?
I found a local company that sells, repairs, recalibrates, and stock secondhand units....
See anything there that might do as a starter scope?
Just to add,
Absolutely everything I have purchased off Eeekbay has been broken or not functional in some way, even guarantied good units. Shipping back across the border from Canada is a no flier after paying duties and brokerage fees.
For something like a primary 'scope, I'll buy new only. It's okay to buy secondary 'scopes used. Assume there is something wrong. Even if the picture is very good. (oops, we must have shipped the wrong one).
Pay attention to the brands and model numbers! Old Tek scopes have no real support, and newer there is poor access to parts and information. Philips have terrible reliability problems (I have one from new, PM series). HP stuff is better for information and access to parts. Old ones require donor units. I find that the HP stuff has a much higher build quality over most other units.
Pay attention how hot a unit runs. Philips "combi" scopes run hot as do parts of the PM 30xx series. New Tek units (DPO4000) run stinking hot somewhere - I will not touch one for that reason alone. Watch the size. Some older 'scope systems are huge, possibly making your power meter spin. The newer DPO4000 series from Tek is larger than your average scope (ie: it may not fit where you want to put it).
-Chris
Absolutely everything I have purchased off Eeekbay has been broken or not functional in some way, even guarantied good units. Shipping back across the border from Canada is a no flier after paying duties and brokerage fees.
For something like a primary 'scope, I'll buy new only. It's okay to buy secondary 'scopes used. Assume there is something wrong. Even if the picture is very good. (oops, we must have shipped the wrong one).
Pay attention to the brands and model numbers! Old Tek scopes have no real support, and newer there is poor access to parts and information. Philips have terrible reliability problems (I have one from new, PM series). HP stuff is better for information and access to parts. Old ones require donor units. I find that the HP stuff has a much higher build quality over most other units.
Pay attention how hot a unit runs. Philips "combi" scopes run hot as do parts of the PM 30xx series. New Tek units (DPO4000) run stinking hot somewhere - I will not touch one for that reason alone. Watch the size. Some older 'scope systems are huge, possibly making your power meter spin. The newer DPO4000 series from Tek is larger than your average scope (ie: it may not fit where you want to put it).
-Chris
anatech said:
I seem to have had exactly the opposite experience -
The two Tek scopes I have bought online (A 2445A on EBay ex Singapore and a 2465A on a local auction site) have both turned out to be "How did I survive this long without these" purchases.
Top whack scopes at decent prices. I don't miss my old Trio/Kenwood (which I did buy new) one little bit.
Cheers
M
Hi mobyd,
That dealer (something99) seems to be pretty good, but shipping is murder to Canada.
It seems that there are many less-than-honest people hanging out in North America. 🙁 I've purchased a few things that were in need of a ton of work from me. Even a pair of Tek 2235's that are semi functional. I won't buy any 24xx series due to the higher cost and the module issue. If one could be sure a 24xx series would last, it would be an excellent buy.
I've even had a number of flood damaged instruments (water babies) that were unmistakable. So in North America, assume it's busted. If it works, then you are ahead of the game.
-Chris
That dealer (something99) seems to be pretty good, but shipping is murder to Canada.
It seems that there are many less-than-honest people hanging out in North America. 🙁 I've purchased a few things that were in need of a ton of work from me. Even a pair of Tek 2235's that are semi functional. I won't buy any 24xx series due to the higher cost and the module issue. If one could be sure a 24xx series would last, it would be an excellent buy.
I've even had a number of flood damaged instruments (water babies) that were unmistakable. So in North America, assume it's busted. If it works, then you are ahead of the game.
-Chris
Perhaps you can find small companies importing oscilloscopes and other test instruments directly from manufacturers, working on reasonable mark-ups, offering new technology equipment which comes with a guarantee.
One such company can be found at : Oscilloscopes :: Test and Measurment Instruments C.C.
This way there is no risk involved in purchasing used test instruments.
One such company can be found at : Oscilloscopes :: Test and Measurment Instruments C.C.
This way there is no risk involved in purchasing used test instruments.
craigslist scopes
On craigslist, it is a cash face to face transaction, no reputation required. I saw a scope listed for $25, took a transistor radio and a plug for a signal source, proved that the screen and trigger circuits work. Cool. Calibration is off, but I have 11 cent zeners to give me some sort of reference on voltage, and the wall voltage leaking out of my finger gives me some sort of reference on time. It is not that far off, about 25 %. Worth every bit of $25 even if obsolete for any sort of digital work. I'm fixing a Hammond organ and a preamp this month, 20 mHZ is fine.
On craigslist, it is a cash face to face transaction, no reputation required. I saw a scope listed for $25, took a transistor radio and a plug for a signal source, proved that the screen and trigger circuits work. Cool. Calibration is off, but I have 11 cent zeners to give me some sort of reference on voltage, and the wall voltage leaking out of my finger gives me some sort of reference on time. It is not that far off, about 25 %. Worth every bit of $25 even if obsolete for any sort of digital work. I'm fixing a Hammond organ and a preamp this month, 20 mHZ is fine.
That was true in the past, but now HP is pretty bad quality, as a friend of mine found out.
Another use for the Kill-a-Watt... - Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com
I believe HP sold their oscilloscope division to Agilent so hardware should not be a problem. Firmware bugs are definitely annoying, though.
Do like I do. Sacrifice one of this year's vacation getaways to the Caribbean and get yourself a new scope instead. Actually a few years ago I sacrificed two years worth of vacations and splurged on a Tektronix TDS2024B. No regrets whatsoever.
Hi star882,
Agilent is HP, the test equipment division.
I'm interested in why you think the quality is down ... ahhhh, you're talking about their computers! No relation to the test equipment division at all. If you want to see really low quality, look at ECS products or Emachines. Total scrap.
I've played with Agilents new stuff. Absolutely lovely equipment. Having also played with new Tek, LeCroy and others in the same time period, I feel I can justify my comments. For me, an MSO6000 series machine (four channels would be nice) at about 500 MHz would satisfy what I need from a 'scope. I'd love more, but the prices rapidly escalate past the price of a nice new car. I can't afford any of it, so this is all but a pipe dream.
I did pick up a non-functional HP 1722A. 275 MHz, two channel. I'm looking forward to checking this thing out once I get it operating. I hear they don't trigger well, but we'll see. I also have a broken Tek 468, so if I can fix both .... I'll better understand what the gripes are all about.
With costs for DSP solutions, memory and improvements to A/D converters and op amps, the newer 'scopes are packing a ton of performance into a small box. For my money though, you will need an analog 'scope as well until the resolution of DSOs gets better. Most are only 8 bit vertical with some special modes at 12 bit vertical resolution. Don't expect a 16 bit solution, and from what I've been able to find out, most analog systems are really only good to about 14 bits of resolution once noise and other factors are considered.
-Chris
Agilent is HP, the test equipment division.
I'm interested in why you think the quality is down ... ahhhh, you're talking about their computers! No relation to the test equipment division at all. If you want to see really low quality, look at ECS products or Emachines. Total scrap.
I've played with Agilents new stuff. Absolutely lovely equipment. Having also played with new Tek, LeCroy and others in the same time period, I feel I can justify my comments. For me, an MSO6000 series machine (four channels would be nice) at about 500 MHz would satisfy what I need from a 'scope. I'd love more, but the prices rapidly escalate past the price of a nice new car. I can't afford any of it, so this is all but a pipe dream.
I did pick up a non-functional HP 1722A. 275 MHz, two channel. I'm looking forward to checking this thing out once I get it operating. I hear they don't trigger well, but we'll see. I also have a broken Tek 468, so if I can fix both .... I'll better understand what the gripes are all about.
With costs for DSP solutions, memory and improvements to A/D converters and op amps, the newer 'scopes are packing a ton of performance into a small box. For my money though, you will need an analog 'scope as well until the resolution of DSOs gets better. Most are only 8 bit vertical with some special modes at 12 bit vertical resolution. Don't expect a 16 bit solution, and from what I've been able to find out, most analog systems are really only good to about 14 bits of resolution once noise and other factors are considered.
-Chris
I've bought several video cards, motherboards, 3 Technics receivers, 8 Metcal soldering irons and many tips, 2 Fluke meters and a frequency counter, 3 ATI HDTV Wonder tuner cards and more. 1 Metcal power unit was bad and needed an IRF130 to make it work but I only paid $10 for it. I guess my luck is better than others.
If money wasn't object I'd have Tek 3054 scope but those go for $11600. You might want to check out the Rigol digital scopes. I'll stick with my Tek 475A
G²
Hi G²,
I have had a demo Rigol 'scope here for a week. It's better than what I thought it might be, but nowhere as good as the other 'scopes I have tried. Your luck is far, far better than mine.
There is another issue to think about as well when buying test equipment. When you buy something like an Agilent product, you get about the most reliable product on the market. They also hold their calibration exceptionally well. These two points are actually far more important than you might consider. 10 years go by almost without notice. We expect the test equipment to actually last about 20 years - and for the most part, they have lasted 20 years or longer.
With this in mind, I'm very picky when it comes to placing money on the table. For example ... the Tektronix 'scope I used on demo has a noisy and clearly audible fan noise when it runs at higher speeds. Can you imagine what your bench would sound like with this and other fan cooled equipment. I know understand why test equipment was often installed in 18" rack cabinets with no missing panels. To cut the noise level down. But on a more serious note, I measured the air exhaust to be a full 20 °C warmer than the inlet air. Something is running pretty darn hot in there. My current Philips PM-3070 has died four times so far, simply due to excessive temperatures. The same PCB every time.
Avoid buying anything with a clear problem. Also understand that elevated temperatures will cause components to age far more quickly and calibration to drift. The LeCroy 'scope I tried ran warm, but not as warm as the Tek. The two Agilent models I tried ran far cooler, and the 6000 series 'scope had a similar profile to an analog 'scope (meaning it fits on my bench), and a fan that was not something I noticed.
To be honest, most analog 'scopes are reliable. They will also do most of what we ask of them. DSOs are cool looking, have nifty features and so forth, but they do not behave just like an analog 'scope. Some of the controls are a pain to get to as well with the newer DSOs. You'll find them in menus for the "soft keys" or on a multifunction control. Not user friendly at all. The easiest ones to use were the LeCroy and the Agilent DSOs.
The Tek 475 is supposed to be one of the better 'scopes I've heard. One day I may get a chance to try one. These older Tek units probably represent the best choice for a DIY enthusiast. Just make sure it actually works.
-Chris
I have had a demo Rigol 'scope here for a week. It's better than what I thought it might be, but nowhere as good as the other 'scopes I have tried. Your luck is far, far better than mine.
There is another issue to think about as well when buying test equipment. When you buy something like an Agilent product, you get about the most reliable product on the market. They also hold their calibration exceptionally well. These two points are actually far more important than you might consider. 10 years go by almost without notice. We expect the test equipment to actually last about 20 years - and for the most part, they have lasted 20 years or longer.
With this in mind, I'm very picky when it comes to placing money on the table. For example ... the Tektronix 'scope I used on demo has a noisy and clearly audible fan noise when it runs at higher speeds. Can you imagine what your bench would sound like with this and other fan cooled equipment. I know understand why test equipment was often installed in 18" rack cabinets with no missing panels. To cut the noise level down. But on a more serious note, I measured the air exhaust to be a full 20 °C warmer than the inlet air. Something is running pretty darn hot in there. My current Philips PM-3070 has died four times so far, simply due to excessive temperatures. The same PCB every time.
Avoid buying anything with a clear problem. Also understand that elevated temperatures will cause components to age far more quickly and calibration to drift. The LeCroy 'scope I tried ran warm, but not as warm as the Tek. The two Agilent models I tried ran far cooler, and the 6000 series 'scope had a similar profile to an analog 'scope (meaning it fits on my bench), and a fan that was not something I noticed.
To be honest, most analog 'scopes are reliable. They will also do most of what we ask of them. DSOs are cool looking, have nifty features and so forth, but they do not behave just like an analog 'scope. Some of the controls are a pain to get to as well with the newer DSOs. You'll find them in menus for the "soft keys" or on a multifunction control. Not user friendly at all. The easiest ones to use were the LeCroy and the Agilent DSOs.
The Tek 475 is supposed to be one of the better 'scopes I've heard. One day I may get a chance to try one. These older Tek units probably represent the best choice for a DIY enthusiast. Just make sure it actually works.
-Chris
Star has a little trouble with context, but is otherwise an impressive bot. Her older posts on the refrigeration forums were so incoherent they were amusing, but "she" seems to have evolved greatly since then.
-David
-David
For those interested in the history, HP divested itself of the Test and Measurement section of the company in 2000. That divested portion was spun off as a brand new company and was named Agilent. The HP name stayed with the computer products part of the company.
Hi quietdragon,
Yes. Most anyone you talk to considers that the HP name should have stayed with the test and measurement division. The name had considerable brand recognition and a strong tie to the idea of quality. The current computer products company has been eroding the "good will" that the original brand had earned itself over the decades of supplying excellent test and measurement products.
So far, Agilent is doing far better with it's reputation than HP is. It's sad to see a mark that stood for quality be ground down by en endeavor unrelated to the original corporate activities. HP only began selling computers to run automated test programs, they were not originally considered for public use at all. Now they are a "value brand" not much better than most others, "e-machines" being the cheap junk they've inflicted on us all. I have to admit that I like their better printers and multifunction machines.
Very few software bugs are allowed out with Agilent. They are very pro-active when it comes to the equipment they sell. The Infinium line is interesting as they run on the windows platform. You can even run other apps and surf the web. I have to say I'm disappointed they aren't running some flavor of Linux nicely nailed down. Far more reliable OS that doesn't require so much memory. Come to think of it, Linux doesn't leak memory like Windows still does (or the apps - I don't care which does it.).
-Chris
Yes. Most anyone you talk to considers that the HP name should have stayed with the test and measurement division. The name had considerable brand recognition and a strong tie to the idea of quality. The current computer products company has been eroding the "good will" that the original brand had earned itself over the decades of supplying excellent test and measurement products.
So far, Agilent is doing far better with it's reputation than HP is. It's sad to see a mark that stood for quality be ground down by en endeavor unrelated to the original corporate activities. HP only began selling computers to run automated test programs, they were not originally considered for public use at all. Now they are a "value brand" not much better than most others, "e-machines" being the cheap junk they've inflicted on us all. I have to admit that I like their better printers and multifunction machines.
Very few software bugs are allowed out with Agilent. They are very pro-active when it comes to the equipment they sell. The Infinium line is interesting as they run on the windows platform. You can even run other apps and surf the web. I have to say I'm disappointed they aren't running some flavor of Linux nicely nailed down. Far more reliable OS that doesn't require so much memory. Come to think of it, Linux doesn't leak memory like Windows still does (or the apps - I don't care which does it.).
-Chris
Hello everyone,
I saw this thread and I thought it might be a good place to get some information on scopes.
I currently do not own, nor have ever owned an oscilloscope. I hardly do any work on circuitry, but I'd like to get into building discrete, or even digital stuff, one day. Repairing amplifiers and eliminating noise is certainly within my realm of interest.
So I was wondering if anyone has an opinion as to what features I should look for in a good starter scope. I'm not willing to spend over $300 because frankly it's more of a toy at this point, than a necessary investment.
Have the digital scopes come far enough since this discussion was started???
I saw this thread and I thought it might be a good place to get some information on scopes.
I currently do not own, nor have ever owned an oscilloscope. I hardly do any work on circuitry, but I'd like to get into building discrete, or even digital stuff, one day. Repairing amplifiers and eliminating noise is certainly within my realm of interest.
So I was wondering if anyone has an opinion as to what features I should look for in a good starter scope. I'm not willing to spend over $300 because frankly it's more of a toy at this point, than a necessary investment.
Have the digital scopes come far enough since this discussion was started???
Technological improvements like higher waveform update rate, Intensity gradient/DPO and deep memories have bridged many of the gaps between analog and digital scopes. The intensity gradient feature give you analog-like capabilities that previously were not available in digital scopes.
An externally hosted image should be here but it was not working when we last tested it.
While the deep memory allows you to record for longer times looking for glitches. This is something that is more or less impossible on an analog scope. Other features you gain in digital scopes are advanced triggering (such as off of a particular data packet, runts, glitches), easy mathmatical manipulation, etc.That being said, at your price point, analog is about it. You could pickup a Rigol 1052E (which is resold as the Agilent DSO1000 series) but it lacks many of the aforementioned features (most notably intensity grading). It is hackable to 100Mhz, has 1Mpt of memory but the rest is lacking. The really bang/$ range is around $500-1000. This is where you encounter the Rigol DS1074Z and DS2072A, both stellar oscilloscopes packed iwth a variety of features.
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What do you think about this one? Owon SDS7102 Deep Memory Digital Storage Oscilloscope 2-channel with VGA and LAN interface:Amazon:Industrial & Scientific
Not worth it. Its decent hardware (a bit too much ground noise but the display is nice) but rubbish buggy software, only two channels, no intensity gradient, known fan issues, etc. make it not worth the price. It's features put it much closer to the Rigol 1102E territory but with a larger display and worse software. If you factor in the fact that there is a known hack for the 1052E to convert it to an 1102E then the Owon becomes even LESS of a value from a performance/$ perspective. At $450 its just not that good of a deal.
You can either step down in price to the Rigol 1052E and hack it to an 1102E. You get similar performance and features for around $310-330*. You drop from 10Mpts to 1Mpt and a smaller screen but gain better software. It's a known quantity and as I mentioned before is resold as the Agilent DSO1000 series. It's no slouch, it's just a bit dated compared to what you get if you step-up a bit in price to a newer model.
Your other option, which is what I would do, I would try to swing the extra ~$80-130* and step up to the Rigol DS1074Z.
You gain:
- True digital phosphor technology aka intensity grading aka UltraVision
- Two more channels for a total of 4 channels
- Higher waveform capture rate of around 30k waveforms/sec (not to be confused with sampling rate which is 1Gs/s)
- Well known and reasonably bug-free software (spelling errors excluded)
- The ability to hack it to include: an extra 12 Mpts (24Mpts total), 100Mhz (from 70Mhz), advanced digital decoding (to decode I2C, UART, RS232 signals), advanced triggers (trigger on a variety of different options), recording ability (record 60,000 frames), 500uV sensitivity
*TEquipment has a savings code for EEVBlog members that saves you 6% thats why I give the range of prices.
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