Author Topic: Are old digital scopes worth the money?  (Read 20157 times)

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Offline little_carlos

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Are old digital scopes worth the money?
« on: March 29, 2016, 03:53:53 am »
Are old digital scopes like those lecroy or hp 100 mhz 200msa/s monochrome worth the money? ive seen them on ebay and other places sometimes quite expensive
would you pick one of those or a good analog scope?
 

Online ataradov

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Re: Are old digital scopes worth the money?
« Reply #1 on: March 29, 2016, 04:21:55 am »
Why there is no option for a modern DSO?

If you can pick them up at $100 or so, then it may be a good deal. But there is no chance something really good will go for $100, analog or digital.
Alex
 

Offline Wuerstchenhund

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Re: Are old digital scopes worth the money?
« Reply #2 on: March 29, 2016, 05:17:40 am »
Are old digital scopes like those lecroy or hp 100 mhz 200msa/s monochrome worth the money? ive seen them on ebay and other places sometimes quite expensive
would you pick one of those or a good analog scope?

Yes, I would, if the price is good. Actually, I just bought a HP 54645D 100MHz 200MSa/s MSO for $300. I needed another scope and at first hovered above the "buy" button for a Rigol DS1054z, but then decided against it after someone mentioned "Yaigol" in another thread. 200Msa/s aren't great but good enough for signals up to say 80Mhz. And I get to play Centipede  ;)

The HP 54600 Series is very reliable, they are simple to operate, and the firmware (latest version for these scopes is 2.0) is pretty much bug free. Attach one of the HPIB or serial storage adapters and you even get decent FFT and maths. 2nd hand prices for the HP labelled 54600 have fallen a lot, the Agilent labelled variants (with faster CPU, FDD and a slightly more modern UI) are still noticeably more expensive.

As to LeCroy, I'm not so sure though. The 9400 and 7200 Series scopes are from the '80s, and although they were really nice scopes back then, just because of their age I wouldn't buy them for anything else than nostalgic reasons, The 9300 Series however is newer (early '90s) and most models come with higher bandwidths and sample rates (200MSa/s up to 4GSa/s). They were the first deep memory scopes and offer advanced maths, FFT and analysis. You can even get all software options enabled for little money ($30 or so) or even free (if you burn the GALs yourself), with approval from the manufacturer. Most of the scopes have screen burn (the amber CRTs in these scopes are more susceptible to burn in than the green CRTs of other scopes) but you can still get new CRTs. And service manuals including schematics are available for them as well.

Sometimes you can find these scopes in working condition for reasonable prices if you're patient.

There's a lot of overpriced crap on ebay but in general yes, I'd buy one of these older scopes if their specs are adequate for what I want to do with it.
« Last Edit: March 29, 2016, 05:28:23 am by Wuerstchenhund »
 

Offline little_carlos

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Re: Are old digital scopes worth the money?
« Reply #3 on: March 29, 2016, 05:36:24 am »
Are old digital scopes like those lecroy or hp 100 mhz 200msa/s monochrome worth the money? ive seen them on ebay and other places sometimes quite expensive
would you pick one of those or a good analog scope?

Yes, I would, if the price is good. Actually, I just bought a HP 54645D 100MHz 200MSa/s MSO for $300. I needed another scope and at first hovered above the "buy" button for a Rigol DS1054z, but then decided against it after someone mentioned "Yaigol" in another thread. 200Msa/s aren't great but good enough for signals up to say 80Mhz. And I get to play Centipede  ;)

The HP 54600 Series is very reliable, they are simple to operate, and the firmware (latest version for these scopes is 2.0) is pretty much bug free. Attach one of the HPIB or serial storage adapters and you even get decent FFT and maths. 2nd hand prices for the HP labelled 54600 have fallen a lot, the Agilent labelled variants (with faster CPU, FDD and a slightly more modern UI) are still noticeably more expensive.

As to LeCroy, I'm not so sure though. The 9400 and 7200 Series scopes are from the '80s, and although they were really nice scopes back then, just because of their age I wouldn't buy them for anything else than nostalgic reasons, The 9300 Series however is newer (early '90s) and most models come with higher bandwidths and sample rates (200MSa/s up to 4GSa/s). They were the first deep memory scopes and offer advanced maths, FFT and analysis. You can even get all software options enabled for little money ($30 or so) or even free (if you burn the GALs yourself), with approval from the manufacturer. Most of the scopes have screen burn (the amber CRTs in these scopes are more susceptible to burn in than the green CRTs of other scopes) but you can still get new CRTs. And service manuals including schematics are available for them as well.

Sometimes you can find these scopes in working condition for reasonable prices if you're patient.

There's a lot of overpriced crap on ebay but in general yes, I'd buy one of these older scopes if their specs are adequate for what I want to do with it.
cool, il keep that in mind when i try for a digital scope
btw what do you mean with that "yaigol" thing? are rigol scopes crap or something?
 

Online ataradov

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Re: Are old digital scopes worth the money?
« Reply #4 on: March 29, 2016, 05:40:04 am »
btw what do you mean with that "yaigol" thing? are rigol scopes crap or something?
They are what they are. Sure, they do have lots of problems, but if you look closely, most of those problems are in the areas where old scopes don't even go.

As I learned some time ago, 1054z takes 15 minutes to save 12 Mpts trace. Sure, 15 minutes is a lot, but at least it can do that, compared to those old scopes with 24 kpts of memory.
« Last Edit: March 29, 2016, 05:41:37 am by ataradov »
Alex
 

Offline Tim F

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Re: Are old digital scopes worth the money?
« Reply #5 on: March 29, 2016, 05:53:22 am »
btw what do you mean with that "yaigol" thing? are rigol scopes crap or something?
They are what they are. Sure, they do have lots of problems, but if you look closely, most of those problems are in the areas where old scopes don't even go.

As I learned some time ago, 1054z takes 15 minutes to save 12 Mpts trace. Sure, 15 minutes is a lot, but at least it can do that, compared to those old scopes with 24 kpts of memory.
Agreed. The 1054Z firmware is incredibly complicated compared to an ancient scope like an HP 54645D so it is inevitable that there will be bugs. At least Rigol do generally fix the bugs.

I wouldn't buy an older DSO. Small memory means you barely get any of the advantages of having a DSO over an analogue scope. The noise floors on older DSOs tend to be pretty bad as well.

As far as serviceability I wouldn't say that older DSOs are any more serviceable than a newer scope. A lot of the service manuals for the early DSOs are a long the lines of "do these steps to find out if the logic board is bad, if it is then replace the entire logic board". People often then charge an arm and a leg for the boards because they know there is some poor sod out there still using one of those scopes for some test fixture and will pay a ridiculous amount to get it working again.

With something like a 1054Z there isn't much that would go wrong. With extended use you might wear out the rotary encoders but they are a generic part. I think a few people have been unfortunate enough for the powersupplies to go bad (bad caps?) and you can get replacement LCD displays for them.
« Last Edit: March 29, 2016, 06:00:28 am by Tim F »
 

Offline mos6502

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Re: Are old digital scopes worth the money?
« Reply #6 on: March 29, 2016, 06:49:33 am »
btw what do you mean with that "yaigol" thing? are rigol scopes crap or something?

Not just their scopes. Dave did several videos over a period of several years dealing with multiple failure mechanisms in their DP832 PSU. Like, design choices that betray utter incompetence and total lack of testing and quality control.
for(;;);
 

Offline Wuerstchenhund

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Re: Are old digital scopes worth the money?
« Reply #7 on: March 29, 2016, 07:06:31 am »
btw what do you mean with that "yaigol" thing? are rigol scopes crap or something?

Judge for yourself:

https://www.eevblog.com/forum/projects/project-yaigol-fixing-rigol-scope-design-problems/

I knew about the firmware issues but I wasn't aware of that thread until very recently when someone mentioned it in another thread. And at least for me it was reason enough to decide against investing even just the less than £300 + VAT the DS1054z costs.

The 1054Z firmware is incredibly complicated compared to an ancient scope like an HP 54645D so it is inevitable that there will be bugs.

 :-DD No, it isn't. Seriously. The 54600 Series scopes may be old, but the firmware isn't really less complex than that in the Rigol. Also, most of the advances in functionality that the DS1000z offers are simply down to cheaper and faster hardware and more memory. And we should not forget that the DS1000z is essentially a bottom-of-the-barrel scope, with very basic capabilities. There's nothing overly complex in its firmware.

And I'm not even comparing the Rigol firmware against some really complex firmware as the one in the old LeCroy 9300 scopes.

Using compexity as an excuse of why the DS1000z was released with bug-ladden firmware is laughable. And it's funny how the big brand manufacturers managed to provide even early scopes with very mature firmware, even back then when development toolset were much more crude than today.

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At least Rigol do generally fix the bugs.

Yes, eventually. Today there aren't many firmware bugs left on the DS1000z, but if you bought the scope when it came out you had to wait for quite a while before it reached a state it really should have been when it was released.

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I wouldn't buy an older DSO. Small memory means you barely get any of the advantages of having a DSO over an analogue scope. The noise floors on older DSOs tend to be pretty bad as well.

Maybe if you look at a digital scope from the '80s but the '90s had quite a few DSOs that are much more capable than an analog scope (and even back in the '80s there were some good digital scopes with decent memory and functionality like the LeCroy 9400). Which analog scope does offer maths, waveform analysis, jitter analysis, FFT and so on? Yeah, none.

The noise floor of the HP 54600 Series and the LeCroy 9300 Series is actually quite good. And not all older scopes come with tiny memory. The HP 54645D I bought for example has 1M per channel which is quite useable, plus it comes with the MegaZoom ASIC which offers a very high waveform update rate.

As mentioned, the LeCroy 9300 Series scopes come with up to 8M sample memory.

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As far as serviceability I wouldn't say that older DSOs are any more serviceable than a newer scope. A lot of the service manuals for the early DSOs are a long the lines of "do these steps to find out if the logic board is bad, if it is then replace the entire logic board". People often then charge an arm and a leg for the boards because they know there is some poor sod out there still using one of those scopes for some test fixture and will pay a ridiculous amount to get it working again.

Not really. Finding most parts for a 54600 isn't difficult simply because there's still a very large number of these scopes out there, plus many that get canibalized for parts. The same is true for the 9300 Series from LeCroy, and many other scopes from that vintage. You can even get new CRTs for these scopes.

Also, because the boards on these scopes are a lot less tightly integrated they are in general much easier to repair. If one of the proprietary ASICs have died then repair is often not possible but in this case just get a replacement board from another scope. Thankfully the ASICs in these HP and LeCroy scopes are a lot more robust than some of the special purpose ICs in older Tek scopes.

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With something like a 1054Z there isn't much that would go wrong. With extended use you might wear out the rotary encoders but they are a generic part. I think a few people have been unfortunate enough for the powersupplies to go bad (bad caps?) and you can get replacement LCD displays for them.

Well, as the "Yaigol" thread shows this isn't all that can be wrong in these scopes.

Also, the DS1000z is tightly integrated, with little ways of repairing it. Plus Rigol doesn't even have anything that can be called a 'Service Manual'. It's really a throw away item.
« Last Edit: March 29, 2016, 07:27:07 am by Wuerstchenhund »
 

Offline Fungus

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Re: Are old digital scopes worth the money?
« Reply #8 on: March 29, 2016, 07:31:45 am »
Are old digital scopes like those lecroy or hp 100 mhz 200msa/s monochrome worth the money? ive seen them on ebay and other places sometimes quite expensive

There's nothing wrong with the scopes if you can get them at a bargain price. OTOH they're old.

Yes, eBay is an expensive place to buy test gear.

would you pick one of those or a good analog scope?

I'd pick even a medium/low DSO over an old analog scope. They do stuff the old analog scopes don't do.

The only reason for buying analog is if it has a huge bandwidth which you really need and you got it at an amazing price.

If not? Nope. Why would you want something that takes up your entire bench and does half the things a DSO can do?

 

Online nctnico

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Re: Are old digital scopes worth the money?
« Reply #9 on: March 29, 2016, 07:33:03 am »
IMHO an older digital scope is only worth the money if you need a lot of bandwitdh for a small amount of money.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline Fungus

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Re: Are old digital scopes worth the money?
« Reply #10 on: March 29, 2016, 07:39:54 am »
Also, the DS1000z is tightly integrated, with little ways of repairing it. Plus Rigol doesn't even have anything that can be called a 'Service Manual'. It's really a throw away item.

a) It does a LOT of things very well (it even exceeds its bandwidth specs by a decent margin).

b) It's solidly built, there's no reason at all to think it won't last a long time.

c) You can buy half a dozen of them for the price of what the Oscilloscope Snobs around here will tell you is the minimum oscilloscope acceptable to them.

 

Offline Fungus

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Re: Are old digital scopes worth the money?
« Reply #11 on: March 29, 2016, 07:42:34 am »
IMHO an older digital scope is only worth the money if you need a lot of bandwitdh for a small amount of money.

'Lot of bandwitdh' and 'small amount of money' are mutually exclusive if you're buying online.



 

Offline pxl

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Re: Are old digital scopes worth the money?
« Reply #12 on: March 29, 2016, 07:44:29 am »
btw what do you mean with that "yaigol" thing? are rigol scopes crap or something?
They are what they are. Sure, they do have lots of problems, but if you look closely, most of those problems are in the areas where old scopes don't even go.

As I learned some time ago, 1054z takes 15 minutes to save 12 Mpts trace. Sure, 15 minutes is a lot, but at least it can do that, compared to those old scopes with 24 kpts of memory.

On those time bases, where large mem really kicks in, eg at 500us, which is your preferred memory settings? You may find large mem useful sometimes on every time bases, that is out of question, but what are you using usually?
 

Online ataradov

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Re: Are old digital scopes worth the money?
« Reply #13 on: March 29, 2016, 07:44:39 am »
b) It's solidly built, there's no reason at all to think it won't last a long time.
And the thing is, I don't need the scope to last more than 3-5 years. I'm not marrying it, and there will be something better anyway.

And eBay hunters for all junk can continue to do so, I'll enjoy modern technology and all it has to offer.
Alex
 

Offline tggzzz

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Re: Are old digital scopes worth the money?
« Reply #14 on: March 29, 2016, 07:46:28 am »
Agreed. The 1054Z firmware is incredibly complicated compared to an ancient scope like an HP 54645D so it is inevitable that there will be bugs.

Could you explain in what way it is "incredibly" complex, and why bugs are "inevitable".

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At least Rigol do generally fix the bugs.

HP had a tradition of delaying product shipment until the product performed as specified - hence they didn't have bugs to fix.

When HP did ship a minicomputer too early, Packard sent a two line memo to the manager requesting that HP not ship products until they met their specification. The manager framed the memo, and everybody in HP was told the story for 10-20 years thereafter.

Quote
I wouldn't buy an older DSO. Small memory means you barely get any of the advantages of having a DSO over an analogue scope. The noise floors on older DSOs tend to be pretty bad as well.

As with old cars, you have to choose wisely.
There are lies, damned lies, statistics - and ADC/DAC specs.
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Online ataradov

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Re: Are old digital scopes worth the money?
« Reply #15 on: March 29, 2016, 07:48:04 am »
On those time bases, where large mem really kicks in, eg at 500us, which is your preferred memory settings?
You can configure sampling rate independent of the timebase.

In that instance I needed to capture and decode some proprietary video signal. I was able to capture 3 full frames, which was enough to import it into python and understand the structure of the signal. And as a proof recovering full picture.

Good luck doing that with an old Tek.
Alex
 

Online ataradov

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Re: Are old digital scopes worth the money?
« Reply #16 on: March 29, 2016, 07:50:29 am »
When HP did ship a minicomputer too early, Packard sent a two line memo to the manager requesting that HP not ship products until they met their specification. The manager framed the memo, and everybody in HP was told the story for 10-20 years thereafter.
And now they are out of this business. Cool story, but I'd rather use slightly buggy hardware delivered in timely manner, than perfect thing delivered 2 years tool late and 10x more expensive.

Alex
 

Online nctnico

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Re: Are old digital scopes worth the money?
« Reply #17 on: March 29, 2016, 07:52:20 am »
IMHO an older digital scope is only worth the money if you need a lot of bandwitdh for a small amount of money.
'Lot of bandwitdh' and 'small amount of money' are mutually exclusive if you're buying online.
I paid $225 for a working 4 channel 500MHz Tektronix TDS510A from Ebay 6 or 7 years ago. Even including shipping it was a bargain.
« Last Edit: March 29, 2016, 07:54:08 am by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline Fungus

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Re: Are old digital scopes worth the money?
« Reply #18 on: March 29, 2016, 07:53:23 am »
On those time bases, where large mem really kicks in, eg at 500us, which is your preferred memory settings? You may find large mem useful sometimes on every time bases, that is out of question, but what are you using usually?

Most (all?) DSOs have an "auto" setting for memory size. In auto mode they choose a memory size that gives a good update rate for the selected time base.

Most of the time you can just leave it in auto mode and it will be good.
 

Offline Wuerstchenhund

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Re: Are old digital scopes worth the money?
« Reply #19 on: March 29, 2016, 07:54:23 am »
Yes, eBay is an expensive place to buy test gear.

Is it? Compared to what exactly?

I got a ton of great deals on ebay that I couldn't have found anywhere else. Yes, there's a lot of overpriced crap, but that's just the noise. It sometimes takes patience, and you need to know what you want and what stuff is worth.

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a) It does a LOT of things very well (it even exceeds its bandwidth specs by a decent margin).

Not saying it doesn't.

Quote
b) It's solidly built, there's no reason at all to think it won't last a long time.

We'll see how long it lasts, but even I wouldn't complain if a bargain basement scope doesn't last as long as a big brand scope. That's one reason the former is so cheap.

Still, it's a complex product, and like any complex product it can fail.

Quote
c) You can buy half a dozen of them for the price of what the Oscilloscope Snobs around here will tell you is the minimum oscilloscope acceptable to them.

Not sure what a "scope snob" is but the minimum scope that is acceptable depends very much on the task you want to do with it. For some a DS1000z is enough, for others it isn't. It's not rocket science.
 

Offline tggzzz

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Re: Are old digital scopes worth the money?
« Reply #20 on: March 29, 2016, 07:58:38 am »
When HP did ship a minicomputer too early, Packard sent a two line memo to the manager requesting that HP not ship products until they met their specification. The manager framed the memo, and everybody in HP was told the story for 10-20 years thereafter.

And now they are out of this business.

Not an astute observation...

HP were in the business for 35 years after that story occurred. In case you hadn't noticed, over 35 years the computer industry changed more than a little, and almost all companies are out of "that business".


Quote
Cool story, but I'd rather use slightly buggy hardware delivered in timely manner, than perfect thing delivered 2 years tool late and 10x more expensive.

Now you are magicking silly numbers out of thin air to attempt to justify a silly contention.
« Last Edit: March 29, 2016, 08:09:58 am by tggzzz »
There are lies, damned lies, statistics - and ADC/DAC specs.
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Offline Fungus

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Re: Are old digital scopes worth the money?
« Reply #21 on: March 29, 2016, 08:00:01 am »
IMHO an older digital scope is only worth the money if you need a lot of bandwitdh for a small amount of money.
'Lot of bandwitdh' and 'small amount of money' are mutually exclusive if you're buying online.
I paid $225 for a working 4 channel 500MHz Tektronix TDS510A from Ebay 6 or 7 years ago. Even including shipping it was a bargain.

Could you go out today and get another one like that...?
 

Offline Wuerstchenhund

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Re: Are old digital scopes worth the money?
« Reply #22 on: March 29, 2016, 08:00:27 am »
'Lot of bandwitdh' and 'small amount of money' are mutually exclusive if you're buying online.

Yes, for new kit. For 2nd hand gear it's not. In fact, "lots of bandwidth" can often be had for similar prices as "modest bandwidth".
 

Online tszaboo

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Re: Are old digital scopes worth the money?
« Reply #23 on: March 29, 2016, 08:12:29 am »
I would buy a HP 54600 series MSO for 250-350 bucks. They are selling it kinda for that money. If the screen works well. Just a DSO, I'm not sure. You need to be aware that the digital capabilities are limited compared to a modern scope. It is better than a low end chinese scope. Or a tektronix TDS2000 series. Well anything is better than the TDS.
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Offline Fungus

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Re: Are old digital scopes worth the money?
« Reply #24 on: March 29, 2016, 08:12:34 am »
'Lot of bandwitdh' and 'small amount of money' are mutually exclusive if you're buying online.
Yes, for new kit. For 2nd hand gear it's not. In fact, "lots of bandwidth" can often be had for similar prices as "modest bandwidth".
I'm not sure if that equates to "small amount of money" or not. Modest bandwidth can be expensive, too.  :P

I guess it mostly comes down to shipping costs though. If you live somewhere where shipping is cheap, then... lucky you.
 


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