REVIEW - Rigol MSO5000. Tests, bugs, questions

[kehall]

Increase your time base to 20uSec and then to 3uSec and tell me if this improves your response - post a picture if you can - so we can compare like for like

I'm afraid the scope is in for repair so I can't do anything myself - can you please compare against my settings (top of trace will go off screen of course but only interested in whether you get overshoots like you could see on Ch1 in my screenshot) but they're claiming it as being 'normal' for such overshoots - I'm of the opposite opinion given ch2-3-4 on that screenshot was flat and fine, and I've had no issues with another unit, and also evidenced from what's been said earlier in this thread and other threads, just some more screenshots would really help.

To be honest I think all that's needed is the probe connecting to compensation output, 'default' and then 'auto' pressed, 10x and then twiddle vertical to 50mV or whatever to see if you get any overshooting like that on any of the 4 channels :/

Much appreciated

[noreply]

Increase your time base to 20uSec and then to 3uSec and tell me if this improves your response - post a picture if you can - so we can compare like for like

I'm afraid the scope is in for repair so I can't do anything myself - can you please compare against my settings (top of trace will go off screen of course but only interested in whether you get overshoots like you could see on Ch1 in my screenshot) but they're claiming it as being 'normal' for such overshoots - I'm of the opposite opinion given ch2-3-4 on that screenshot was flat and fine, and I've had no issues with another unit, and also evidenced from what's been said earlier in this thread and other threads, just some more screenshots would really help.

To be honest I think all that's needed is the probe connecting to compensation output, 'default' and then 'auto' pressed, 10x and then twiddle vertical to 50mV or whatever to see if you get any overshooting like that on any of the 4 channels :/

Much appreciated

Do you remember EXACT configuration settings - each setting , like impedance , etc, etc

Basically - press the 'default' button (assuming this has not been redefined in any way), then make whatever settings you want - make notes and post here the settings you make after pressing the 'default' button.

I will copy EXACT and rerun the rests for you.

Also - please check the probe attenuation settings - what were they set to? 1x or 10x - need to know this of cause.

No problem doing this for you - just awaiting your feedback to the above 

Cheers

[NoisyBoy]

Kehall, if you are referring to the probe compensation issue (inability to remove overshoot/undershoot with test signal, no matter how you adjust the screw at the probe) it has been a known issue for 16 months.  It affects some scopes, but not others.  For a healthy unit, all four channel should look the same, with minimal overshoot/undershoot, your picture definitely show an issue with your unit.  I have no idea why Rigol would tell you the channel 1 behavior is normal, you should tell them that it is normal for you to return the scope for a full refund for defects like this.

Last year, there were rumors that newer firmware would correct the issue, but it was pretty clear that it did not address the problem for most people with the issue even with the newest firmware.  There were some successful attempts by replacing the ifcal.hex with a copy from a healthy scope, jump over to this set of discussion here to learn more: https://www.eevblog.com/forum/blog/new-rigol-scope/msg2241315/#msg2241315

If it is a new scope, my suggestion is to send it back for a replacement, you should not have to fix something like this and the unit should have never passed QA.  If you have had it for a while (I believe all units should still be under warranty), I would send it back and let them deal with it.  Who knows, they may just change the mother board and you may get the 1.01 hardware and a fresh calibration. 

Hope this helps.

[kehall]

Kehall, if you are referring to the probe compensation issue (inability to remove overshoot/undershoot with test signal, no matter how you adjust the screw at the probe) it has been a known issue for 16 months.  It affects some scopes, but not others.  For a healthy unit, all four channel should look the same, with minimal overshoot/undershoot, your picture definitely show an issue with your unit.  I have no idea why Rigol would tell you the channel 1 behavior is normal, you should tell them that it is normal for you to return the scope for a full refund for defects like this.

Thanks - ok I'll explain the whole story. The image with the overshoot on Ch1 was the first scope I received in March. I indeed had this replaced straightaway. The replacement I received had perfect response - all 4 channels looked like Ch2 on that image, no overshoots.

Only problem was there was a delayed fault with that scope which I didn't find until May (hadn't needed to use the scope in ernest until then), after half an hour or so of time in use the very bottom of the touchscreen would not respond, and worse, would randomly activate things at the bottom of the screen, changing settings by itself making it unusable.

This went back to Rigol for repair back in June... It came back with a new board (1.01) but all 4 channels then had the overshoot. Worse still, the touchscreen fault had not been repaired either!

It went back AGAIN a couple of weeks ago to be replaced by a factory brand new unit, I mentioned them to check the overshooting issue and they say that the new one has the same overshoots and that it's normal, and they say a Tektronix they found the same on??!??

I mentioned this thread, and the ifcal.hex (lfcal.hex?) stuff - they say that file didn’t come from their R&D and the overshoot / undershoot which was visible in the past with some devices were resolved with the firmware upgrades...

I don't think they're speaking to the right person in their R&D if so, they ought to know the scope!

They say it's normal (can't expect 50mV resolution on a 5v p-p signal?) and I can either have this replacement or a refund, very much Hobson's choice

[kehall]

Do you remember EXACT configuration settings - each setting , like impedance , etc, etc

Basically - press the 'default' button (assuming this has not been redefined in any way), then make whatever settings you want - make notes and post here the settings you make after pressing the 'default' button.

I will copy EXACT and rerun the rests for you.

Also - please check the probe attenuation settings - what were they set to? 1x or 10x - need to know this of cause.

No problem doing this for you - just awaiting your feedback to the above 

To be honest if you have the overshoots I think you'd have said by now, but ok try this (from memory and photos):

Press Default
Connect Ch1 and Ch2 to probe compensation output, ground clip to ground (not that this should be needed)
Press Auto

probe set to 10x,

should get pretty much the display in the quick setup/manual @ 200us/500mV? something like this:



set attenuation 10x just to correct the values at the bottom

now 'zoom in' on the vertical (timebase can stay same, its not really that relevant) to the bottom edge of the display to 50mV (bottom edge can stay centred on screen). Interested in what you see.

Thanks again

[kehall]

If it is a new scope, my suggestion is to send it back for a replacement, you should not have to fix something like this and the unit should have never passed QA.  If you have had it for a while (I believe all units should still be under warranty), I would send it back and let them deal with it.  Who knows, they may just change the mother board and you may get the 1.01 hardware and a fresh calibration. 

This is what they claim is ok on the brand new unit and not 'something they see as a bug'...



It is less of an overshoot but a significant overshoot all the same - BUT Ch 2,3,4 on the first unit I had and ALL 4 channels on the replacement were really nice and flat, so this feels wrong and what if I need to trust the display when checking higher frequencies than the in built 1Khz 5vp-p square probe compensation output, wouldn't take much for the overshoot to really get in the way?!

They say it doesn't overshoot as much on mV signals so it's ok and if I expect to get flat response at 50mV on 5v P-P maybe this scope is not for me?

Frustrated!

As you know self cal doesn't change anything but I think there should be a lower level calibration routine to build that lfcal.hex file that the service centre (and their R&D contact) doesn't know about.

[noreply]

OK, I repeated the test - as per your instructions / settings

DS14 and 15 are at lower vertical resolution

DS25 and 26 are at higher vertical resolution

As you can see I offset the vertical slightly - so you can see the separate channel traces

Keep in mind - I DID NOT ADJUST THE PROBES in any way - to try to compensate - this is straight from the 'packet'

I don't use probes much - have direct BNC connections - that's why I never calibrated as yet.

The interesting thing is that the probes 'track' each other very well - considering they were not 'calibrated' my me.

If you want me to try to calibrate the probes for a better response - let me know.

Happy to help out.

[NoisyBoy]

I don't use the MSO5000 much these days and it is stashed away behind other equipment.  I can try to take some pictures when I have a chance.  But I can tell you this is not right, it should be nice and flat.

I don't know what type of overshoot is acceptable to Rigol, even my $30 scope does better with the test signal.  If I were you, I would not have accepted this as normal and put up with it, and I would have them keep replacing it until it is right.  If they can't, get a refund and buy something else.  Given the level of support you get from Rigol in the UK, I would shop other brands as there have been some pretty interesting new scopes out there.

I find it disheartening that they tried to convince you even a Tek does that and it was perfectly normal.  Either their support is clueless, or they treat their customers like they are clueless, neither is acceptable in my book.  Based on their latest arrogent response to you, I would just get a refund and buy a different brand. 

[noreply]

@NoisyBoy

I just made some more tests - this time 'tuned' the probes - yes of cause you can reduce the overshoot - my probes were not calibrated

DS27 shows result after probe adjustment.

I offset the vertical in DS28 - so you can see the CH1- but its not 100% correctable - slight overshoot?

I then tried the SAME probes on CH3 and CH4 - see DS29

Then back to CH1 and CH2 - see DS31

The switching of the channels with the same probes - confirms that the probes are not the problem 

It appears that CH1 has something different internally - possible impedance mismatch - or not set 'spot-on' in factory calibration?

I don't know.

Personally it does not bother me as long as I can understand the reason for this behavior.

Why CH1 only?


Is there something specific with CH1?

Hope the above helps you out kehall - at least you now have an independent benchmark.

Let me know if there is anything else I can do?

Take Care

EDIT:

found way to delete the doubble image and correct

[tv84]

EDIT:
Is there a way to edit / delete unwanted attachments?

Sure there is. You edit the msg and de-select the image.

[kehall]

I don't use the MSO5000 much these days and it is stashed away behind other equipment.  I can try to take some pictures when I have a chance.  But I can tell you this is not right, it should be nice and flat.

I don't know what type of overshoot is acceptable to Rigol, even my $30 scope does better with the test signal.  If I were you, I would not have accepted this as normal and put up with it, and I would have them keep replacing it until it is right.  If they can't, get a refund and buy something else.  Given the level of support you get from Rigol in the UK, I would shop other brands as there have been some pretty interesting new scopes out there.

I find it disheartening that they tried to convince you even a Tek does that and it was perfectly normal.  Either their support is clueless, or they treat their customers like they are clueless, neither is acceptable in my book.  Based on their latest arrogent response to you, I would just get a refund and buy a different brand.

Thanks... It is disappointing and frustrating as it seems like it otherwise is a very capable device...

Can this forum do polls I wonder, it'd be interesting to do a poll and find out who has good and bad units - its like there's someone on the production line thats get the factory calibration right and others don't care so much!

UPDATE: created poll: https://www.eevblog.com/forum/testgear/rigol-mso-5000-overshoot-or-not-overshoot/

[kehall]

Hope the above helps you out kehall - at least you now have an independent benchmark.

Let me know if there is anything else I can do?

Take Care

Thanks noreply - what firmware is this running please as the trace looks fairly thick - suggesting possibly before 1.1.4.8 (or you're in quite a noisy environment)?

[noreply]

Hope the above helps you out kehall - at least you now have an independent benchmark.

Let me know if there is anything else I can do?

Take Care

Thanks noreply - what firmware is this running please as the trace looks fairly thick - suggesting possibly before 1.1.4.8 (or you're in quite a noisy environment)?

Pleasure to be of help - this is why we are all here - to help each other!

My firmware is 00.01.03.00.01
Hardware 01.01.000

Yeah, I do have a 'noisy' environment - but there is a lot of jitter / noise on the trace.

I have been to busy to check the latest FW updates

I use the MSO for RF design and frequency stability tests - so precise voltage readings not an issue for me - even to the extent I did not calibrate the probes until just now.

I will try to check why the 'noise' on the trace and update to the latest FW soon.

I presume - this was an issue before with earlier FW??

Also - as mentioned in earlier post - the overshoot problem is only on CH1 - did you experience similar?

If so, would be nice to see if there is some underlying reason for this - as if it happens in more than one device - there must be some HW or tweek that is common to all of the MSO5074's??

Take Care

[NoisyBoy]

I dug out the Rigol and did a few quick snapshots, I also tried to test a few other probes from other scopes to check the difference probes make:

In photo DS0, Ch1 and Ch2 are both with the 350MHz Rigol probes that came with the scope.
In photo DS1, Ch1 is the same, Ch2 is tested with a 500MHz probe from the LeCroy scope.
In photo DS2, Ch1 is the same, Ch3 is tested with a 500MHz probe from the Keysight scope.
In photo DS3, Ch1 is the same, Ch4 is tested with a 500MHz probe from the R&S scope.

The probe bandwidth and quality makes a difference, as you can see in the more square corners.  Both I don't see noticeable overshoot/undershoot as you had mentioned. 

I hope that helps.  I hope Rigol will do the right thing and correct the overshoot problem instead of telling you it is normal.

[kehall]

I will try to check why the 'noise' on the trace and update to the latest FW soon.

I presume - this was an issue before with earlier FW??

Also - as mentioned in earlier post - the overshoot problem is only on CH1 - did you experience similar?

Thanks, yes I know there was a FW update which reduced the noise somewhat but looks like you're already ahead of that version anyway so probably the environment to a degree.

I wish there was a better X-Y mode resolution though (I know its a tricky process with digital sampling) but thats another topic.

My first unit bought March was the one with that overshoot on channel 1 only, which made it rather obvious. It was a 1.00 unit - I spent a bit of time trying various things but the supplier intervened and swapped with another. That one had flat, consistent response on all 4 channels, so I was happy until the touchscreen threw a wobbler after some time powered up.

It went back for repair in May (really should have been replacement then too as I believe was DOA, just undiscovered), but anyway the board got replaced rather than the screen, so it came back with the same screen fault and a new 1.01 board that then had overshoots on all 4 channels...

It's back in for repair now, and offered new replacement, but that has overshoots on all four too so I'm in the middle of trying to get that sorted before they send it me - I don't really want a refund, it doesn't really help anyone - I just want a working, consistent, trustworthy device, and if we can get this issue addressed it'll serve a greater purpose!

NoisyBoy, thank you for those images, that's a great help too. I'll point Rigol and my supplier at this thread again (and the poll if it gets any responses)

[Pulsepowerguy]

Kehall, if you are referring to the probe compensation issue (inability to remove overshoot/undershoot with test signal, no matter how you adjust the screw at the probe) it has been a known issue for 16 months. 

Noisyboy, The trimmers on the probes only affect the 10X setting. They have no effect in the 1x position which I think is to be expected.

[Pulsepowerguy]

Noreply, my channel 2 is not in agreement with the others (as I have shared on page 8 ), and it seems that several other folks have had similar experiences. I in the process of getting a replacement and will post results when I get it. Rigol NA support has been very good so far.

I am getting the impression that the calibration process at the factory is a bit spotty. There has been mention of a file that is responsible, but it is likely to be scope-specific and one version is not suitable for all scopes (obviously).

[noreply]

I wish there was a better X-Y mode resolution though (I know its a tricky process with digital sampling) but thats another topic.

Yeah - I found the same - BUT I guess my specific reason for using X-Y is to see the 'spinning circle' - where the 'spin' is under observation (the period) no the thickness of the trace.

I also posted earlier - if there is a way to display CH1 and CH2 while displaying the X-Y

This is possible on the 1054z - so unless I missed something in the menus - perhaps they remove this feature from the 5000 series??

[NoisyBoy]

Pulsepowerguy, agreed, the compensation were only done at 10X.  All my tests were done using the 10X setting on the Rigol probe, and 10X setting within the scope. 

For all the other probes I used in the test, they are all 10X only probes. 

[Pulsepowerguy]

I wish there was a better X-Y mode resolution though (I know its a tricky process with digital sampling) but thats another topic.

Yeah - I found the same - BUT I guess my specific reason for using X-Y is to see the 'spinning circle' - where the 'spin' is under observation (the period) no the thickness of the trace.

I also posted earlier - if there is a way to display CH1 and CH2 while displaying the X-Y

This is possible on the 1054z - so unless I missed something in the menus - perhaps they remove this feature from the 5000 series??

Hit the 'Acquire' button and then 'Time base mode' (XT, XY, Roll)

[noreply]

Hit the 'Acquire' button and then 'Time base mode' (XT, XY, Roll)

Yeah .. this is correct - but it will put you the X-Y plot ONLY or the Time Base mode ONLY

What I am trying to do is display BOTH timebase - the CH1 and CH2 lots and 'below' this the X-Y plot

Like - take the DS32 and put DS33 below this image - to form one large image waveform containing BOTH plots at the SAME time

This IS possible on the 1052z

[noreply]

I wish there was a better X-Y mode resolution though (I know its a tricky process with digital sampling) but thats another topic.

Interesting - just trying to see 'why' digital sampling would have this inherent side-effect?

[Pulsepowerguy]

Sorry, noreply. I misunderstood your question (as is usual for me).

[noreply]

Sorry, noreply. I misunderstood your question (as is usual for me).

No problem - was difficult to visualize from description.

I have attached a photo I managed to capture from YouTube -  as it shows exactly what I am asking about.

Much easier to understand

[kehall]

I wish there was a better X-Y mode resolution though (I know its a tricky process with digital sampling) but thats another topic.

Interesting - just trying to see 'why' digital sampling would have this inherent side-effect?

The way I understand it - X-Y on a 'proper' analogue scope is easy as the signals literally drive the horiz and vertical amps and therefore the plates in the CRT, you can only have one 'spot width' at any one point on the screen.
A digital scope has to sample the signal voltages passing through an ADC, and then draw pixels. These samples are done thousands/millions/billions of times per second and plotted on the screen.
Noise levels (externally, and within the scope) mean that these samples can vary 'wildly' and therefore you see the square rather than a single point you see when XY is on a digital scope.

Averaging or some other filtering should really help but it doesn't look like the MSO5000 has this right yet, and worse still, this noise seems to occur irrespective of any adjustments to attenuation/amplification, as you can see in these two images (of the same signal, two sine waves from in-built generator one slightly higher frequency than the other so you have a bit of a slowly 'rotating/flipping' circle showing phase change).

The 2nd image is just the same but at 100V/div, and you see the trace 'width' doesn't change. The display is suggesting there’s around 20-25V of noise on a 5V amplitude signal which clearly cannot be!