Tek TDS540D or Rigol11054Z

[WaveyDipole]

The Rigol is brand new, the Tek is used, but both at the same price. Which one would you go for?

[tggzzz]

Whichever one will be better at measuring the circuits you are interested in. So, would you like to provide more information?

Of course, a faulty scope won't measure anything.

[AndyC_772]

The TDS5xx scopes are very old now, and if I were in your position, I'd go for the newer scope - if it'll do what you need, of course. I've owned a TDS540 and a TDS754D, and although they worked brilliantly, I always worried that they were on their last legs and liable to die at any moment. They're quite noisy and put out about 400W of heat too.

If you need 500 MHz, then there's no contest. If you don't, you'll save a lot of desk space with the Rigol.

[BravoV]

Simple question, if it breaks down after the 2nd time you powered it on, do you have the skill to repair it ? and required tools, usually an "extra" working scope is needed if its serious problem.

Say you have the skill and the extra tools & scope to fix it, what happened if the damage part is an unobtainium chip ? 

[tggzzz]

Another simple question. Can you assure the signal integrity of a modern digital signal (risetime 1ns or less) with a 50/100MHz scope?

So, what does the OP intend to do with the scope?

[femtohertz15]

Might end up getting another 540 for parts.

Average on the 'bay is about $1/MHz.  So maybe $400 for a TDS540 isn't too a bad deal, for a bandwidth scope.

[snoopy]

I bought a Tek TDS784A at a very good price because my Hantek 200MHz scope just wasn't up to the task of measuring 100MHz SDRAM clock signals etc. This scope has 1GHz bandwidth on all 4 channels with up to 4Gs/s single shot sampling on one channel and 250 Gs/s for repetitive signals which is a fantastic performance and puts the Hantek to shame.

However even though it worked, it failed the SPC and acquisition tests so I had to replace all 16 relays in all of the the attenuators which fixed the SPC problem but still had the Acquisition fail which was subsequently traced to dry joints on one of the demultiplexer chips on the acquisition board.

The moral of the story is that you may have to do some work on these scopes if you buy one. Apparently the TDS540 was notorious for a bad batch of leaky electrolytic capacitors so that maybe the first thing you may want to change. There are some good youtube videos on these scopes. Checkout the youtube videos from TekHobbyCap and FeedbackLoop for more indepth info on these scopes and their issues.

These are a great scope even compared to todays scopes. If you want brute performance on a budget these scopes will still out perform your rigols and siglents by a long mile.

Cheers

[nctnico]

These are a great scope even compared to todays scopes. If you want brute performance on a budget these scopes will still out perform your rigols and siglents by a long mile.

I agree. If you don't need protocol decoding then the TDS500 or TDS700 series are great and their issues are well known. Besides that: as an EE you should be able to fix your own scope!

[WaveyDipole]

Sorry, I should perhaps have provided more infortmation. At present, the scope is just for hobby use and the occasional repair. I am currently working with Arduino although may eventually move on to FPGA based boards. I currently have a Tek465 which I did have to repair a couple of times. Of curse, this is even older than the TDS540 which seemed to be a reasonable deal on the $1 (or £1) per megahertz scale, but as some have pointed out, will also likely need some maintained, e.g. caps replaced which I am capable of doing. I don't have any probes for 500MHz, but I do have one far east one that is rated up to 350MHz, although I accept that in reality it may not perform up to that level so the cost of a decent probe may need to be factored in at some point - although I understand it is possible to DIY as well. I don't think that the Tek has anyware as much storage as the Rigol, but the 2Gsa (1Gsa per channel) seemed appealing. I have no idea how it fares on the measurements and maths front compared to a modern Rigol and it doesn't have colour. The Rigol has the advantage of being smaller, which will be important since I have limited work space. I must admit, I thought the rise time on the Tek would be better than that. I am also curious as to why they put out so much heat?

[David Hess]

Assuming that it works, I would go with the TDS540D and doubly so if it has option 2F because then it can be used as a network analyser.

[WaveyDipole]

It has only option 1F fitted. He does also have a TDS460 (400MHz) with options 1M, 05 and 2F.
BTW, what is the floppy drive used for? Can one convert this to USB?

[Wuerstchenhund]

The Rigol is brand new, the Tek is used, but both at the same price. Which one would you go for?

That depends on what I'd wnat to do, really. Because this isn't a decision between equivalent scopes.

The Tek TDS540D was a scope sold at the end of the '90s and therefore is pretty old. Some variants also suffered from bad caps which tend to leak and in the process often also damaged boards beyond economical repair (although I'm not sure if the D variant was affected). You get 500Mhz BW and 2GSa/s (1GSa/s in four channel mode) as well as up to 8Mpts. Due to the slow architecture high waveform rates are only achieved in a special mode where the scope reduces the amount of data it processes and in which no measurements can be done. In normal mode the waveform rates are quite low, though, and intensity grading is limited to 16 levels only. The good thing is that the TDS540D lacks the NuVision color display  (which is pretty much a monochrome CRT with an LCD shutter in front of it to create the impression of color) of the bigger models, as many of the shutters tend to have deteriorated or failed over time. If the TDS540D works it's an OK scope but it can be a bitch to repair.

The Rigol DS1104z is a low-cost bottom-of-the-barrel scope with 100MHz BW (and if hacked this only goes up to some 150MHz), which isn't really comparable to the 500MHz Tek. It's smaller than the Tek, draws less power, and comes with a modern widescreen color TFT. The Rigol also has more sample memory as the Tek, and can do some simple serial decoding. And like any decent scope it doesn't rely on a special mode for high update rates but achieves them in normal mode. When it came to market the DS1000z Series was full of bugs but by now most of them seem to have been fixed. And if it fails then you're covered with 3 year warranty.

FFT is pretty basic on both scopes, and neither come with any decent search or analysis tools for data in sample memory.

If the choice has to be between those two scopes only then I'd say the Rigol is the better offering unless you really need the higher BW the Tek offers (in which case I'd have a look at other possible alternatives).

These are a great scope even compared to todays scopes.

No, not really. I understand that for someone coming from a Hantek this is probably a huge upgrade, but reality is that these old scopes can't hold a candle against a decent newer scope.

If you want brute performance on a budget these scopes will still out perform your rigols and siglents by a long mile.

Only in BW. Rigols and Siglents have a lot of issues (mostly bugs) but in general their scope platforms are faster than those old Teks.

[tggzzz]

Another simple question. Can you assure the signal integrity of a modern digital signal (risetime 1ns or less) with a 50/100MHz scope?

A 500MHz scope has ~0.7ns intrinsic rise time, how can that be used to measure a 1ns rise time accurately?

It is a damn sight more useful than a 50/100MHz scope - which certainly won't catch glitches!

In addition, often you are interested in relative delays, and you can measure that to a higher resolution. Caveat: would have to check exactly how a specific digitising scope's front end worked; it certainly is possible using analogue scopes.

In addition, measuring over/undershoot is more important than the risetime.

Also, you need a fast enough probe to do signal integrity jobs, which is, sometimes more expensive than the scope itself.

Of course. 50ohm coax and low impedance Z0 probes can be found at reasonably cheap prices.

So practically, using an universal Chinese probe (rated 100MHz, but usually work well up to 350MHz) and a Tek 500MHz scope, you can expect 250~300MHz system BW, which translates to ~1.2ns rise time.
I wouldn't use it to measure rise/fall edge of anything sharper than 2.4ns.

Shrug; if you use a piece of wet string you will get even worse results.

[tggzzz]

I don't have any probes for 500MHz, but I do have one far east one that is rated up to 350MHz, although I accept that in reality it may not perform up to that level so the cost of a decent probe may need to be factored in at some point - although I understand it is possible to DIY as well.

It isn't just the probe, it is also how you connect it to the UUT. A traditional "high" (cough) impedance probe with a 6" ground lead will resonate at ~100MHz. There are ways to reduce that tendency, but not to eliminate it.

Low impedance probes can be DIYed, but unsurprisingly they aren't as good as commercial ones. People often solder a 450ohm resistor to the points of interest, and solder a 50ohm coax to that resistor and ground.

It is worthwhile keeping an eye out on fleabay.

[snoopy]

These are a great scope even compared to todays scopes. If you want brute performance on a budget these scopes will still out perform your rigols and siglents by a long mile.

I agree. If you don't need protocol decoding then the TDS500 or TDS700 series are great and their issues are well known. Besides that: as an EE you should be able to fix your own scope!

I was thinking of getting a Rigol DS1054z just for protocol analysis I think you need to own a few different scopes and take advantage of each scopes strengths

cheers

[Ivan7enych]

For Arduino projects this Rigol will be much more useful.
Later, if you want to work with higher frequencies, like 430MHz RF transmitters-receivers you would better get a spectrum analyzer.

[WaveyDipole]

Its unlikely that I will be working with anything RF at those frequencies, only standard radio sets, maybe with air band at most. otherwise its will be Arduino, smpsu's, TVs, PC power supplies, HiFi amps and audio, DIY projects and that kind of thing.

I have now seen some photos of the Tek TDS540D and it seems that the screen is cracked. What concerns me more is that what is supposed to be a rectangular display looks rather skewed. The spec says its a 'phosphor display' which I take to mean a CRT although its dimensions seem substantially less deep than the average analogue oscilliscope. If its a CRT, then it would seem to be damaged in some way so I think I will have to give it a miss.

Anyone have views on Owon scopes? Are the on par with Rigol and Sigilent?

[nctnico]

The phosphor is simulated but the Tektronix TDS500 series does have a CRT display but it is a short neck tube.

[andy2000]

There is a tinted glass panel covering the CRT.  If there is a crack, it's probably only in this cover. 

The D models were the last of this series of scopes (from 1999-2000), so many of the problems (like leaking caps) were solved by that time.  While that model only has a monochrome screen, it avoids the reliability problems of the LCD shutter color screens. 

[WaveyDipole]

Thanks for that. I appreciate that its probably only the outer glass covering that is cracked, but since this scope has been confirmed to have a CRT, the distorted image seems to suggest further damage to the CRT internals, hence the effect on the geometry. I would suspect that the damage has been caused by a drop.

I was not aware of the LCD shutter, nor its reliability problems, so thanks for the tip. Something I will look to avoid.

Although  am keeping an open mind, I am now tending back towards the Rigol. It seems hard to beat at its current price, but since this would be my first DSO, my very cautious nature seems to be getting the better of me!

[nctnico]

Perhaps you could make a better deal for the TDS540D. Somewhere in the area of $150 to $200.

[AndyC_772]

The colour LCD is a very nice thing to look at, if you get a good one. Because of the technology there's no shadow mask and no convergence issues, though the viewing angle isn't as wide as you might hope.

It's no longer really an issue these days, but I do remember once spending a long time trying to debug a faulty power supply design using a mono scope - which, now I think about it, was probably a TDS540 of some vintage or other. Because the traces all look the same, I didn't notice that two traces had crossed over each other at some point, and I had about 20A flowing the wrong way through a resistor.

Seriously. Colour screen. It'll make your life easier in the long run.

[Wuerstchenhund]

Because the traces all look the same, I didn't notice that two traces had crossed over each other at some point, and I had about 20A flowing the wrong way through a resistor.

Another thing (if I remember right that is, it's been a while) these Teks can only display a single graticule so all traces use the same raster, which doesn't help if there's no color.

Seriously. Colour screen. It'll make your life easier in the long run.

This, or at least a scope that can show multiple graticules so traces can be kept separate (like the HP 54500/54600 Series).

[vk6zgo]

The colour LCD is a very nice thing to look at, if you get a good one. Because of the technology there's no shadow mask and no convergence issues, though the viewing angle isn't as wide as you might hope.

It's no longer really an issue these days, but I do remember once spending a long time trying to debug a faulty power supply design using a mono scope - which, now I think about it, was probably a TDS540 of some vintage or other. Because the traces all look the same, I didn't notice that two traces had crossed over each other at some point, and I had about 20A flowing the wrong way through a resistor.

Seriously. Colour screen. It'll make your life easier in the long run.

Gee,we do need to be hand fed,don't we ?

All the traces on 4 channel analog 'scopes are the same colour,& we managed to not get them mixed up over many decades.

That said,I would recommend the Rigol.
It will be much more usable for general scope work at lower frequencies.

The Tek is obviously great for high frequency work when the time/div setting is quite short.
Due to the smallish memory,it will be unlikely to maintain that very fast sample rate at longer time/div settings.

[nctnico]

What is nice about monochrome Tektronix scopes is that they retain the previous trace in grey on screen. It doesn't sound like much but it works well as some kind of trigger speed dependant persistence feature.