Author Topic: RIGOL MSO1074Z-S, 14 months after purchase  (Read 4684 times)

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Offline prasimix

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RIGOL MSO1074Z-S, 14 months after purchase
« on: January 13, 2016, 03:28:55 AM »
I'd like to hear your opinion since according to the support answer form the RIGOL authorized dealer this topic is closed. I bought a new MS01074Z-S about 14 months ago. During this time it was used frequently and it wasn't abused in any sense (e.g. overvoltage on inputs, no AC mains surges, mechanical pressure on probes and input BNC connectors, etc.). Recently I noticed that something is wrong when no signal is present on any of its 4 inputs. At first I thought that probes are picking up some external noise, but even without probes and when I selected input grounding the situation was not improved a bit. Here is the screenshot with all inputs grounded before I contact their dealer technical support:



Technical support suggest me self-calibration. I follow that and self-calibration begins. After lots of clicking and traces moving around the calibration is successfully finished. After restart I got the following (again all input are grounded):



It seems like an improvement but just selecting the AC coupling even without probe cable connected I got the following on the Ch3 that looks better then others on the above picture:



I sent the same screenshot to the dealer and I got the following response:
Quote
... Rigol compared it to their own devices and with the device specifications, this noise is considered normal and within specs for the MSO1000Z series devices. Unfortunately we can't improve it any more.

With different time base grounded ch3 looks like this:



My question is does anybody experienced the same behavior on not completely new MSO or any other RIGOL's device from the same series/class? Thanks in advance.



« Last Edit: January 13, 2016, 03:32:30 AM by prasimix »
 

Offline Howardlong

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Re: RIGOL MSO1074Z-S, 14 months after purchase
« Reply #1 on: January 13, 2016, 10:31:46 AM »
Looks pretty much identical to mine in the scenarios given.

You are operating at 10mV/div on 10X, you're seeing the ADC noise on the LSBs.
 

Offline prasimix

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Re: RIGOL MSO1074Z-S, 14 months after purchase
« Reply #2 on: January 13, 2016, 08:17:36 PM »
Looks pretty much identical to mine in the scenarios given.

You are operating at 10mV/div on 10X, you're seeing the ADC noise on the LSBs.

Thanks, I noticed that today. For some reason I was convinced that it was much better some times ago. Unfortunately I have no screenshots from that time and obviously self-calibration is all what could be done to improve "reference" state. Next time (if it comes) I'll go fishing for some bigger name.  :D
 

Offline prasimix

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Another day...
« Reply #3 on: January 13, 2016, 08:57:20 PM »
Anyway, as an reference for future buyers, here is what I got this morning (again without any other equipment in closed proximity switched on):



Another day, another luck? After self-calibration the situation was improved. Here is how it looks without probe plugged in and AC coupled:



... or grounded:



So it seems that the new practice would be to starts a day with self-calibration.
 

Offline mcinque

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Re: RIGOL MSO1074Z-S, 14 months after purchase
« Reply #4 on: January 13, 2016, 11:49:23 PM »
Are you sure that you didn't move ANYTHING in your lab? I experencied much noise from switching lamps and wall power adapters; that noise change even moving a hand or a metal can in the surrounding.
I'm basically still a rookie and because of this, even though the best of intentions, I often say bullshit, so never mind.
 

Offline Performa01

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Re: RIGOL MSO1074Z-S, 14 months after purchase
« Reply #5 on: January 14, 2016, 02:23:15 AM »
Your probes probably act as antenna and catch all kinds of interference from the environment.
Your test only makes sense with probes disconnected at least. Even better yet, connect a 50 ohm terminator to the scope input instead. Only then you'll get a consistent picture regarding analog frontend noise.
 

Offline CustomEngineerer

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Re: RIGOL MSO1074Z-S, 14 months after purchase
« Reply #6 on: January 14, 2016, 05:43:59 AM »
I've got a desk lamp on my bench that even with it powered off when I move my hand near it I can see changes on my oscilloscope. Same thing with the ceiling light/fan 5-6 feet away from the scope (though on the same circuit), hanging in the middle of the room.
 

Offline MrSlack

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Re: RIGOL MSO1074Z-S, 14 months after purchase
« Reply #7 on: January 14, 2016, 05:48:18 AM »
That's pretty bad. The noise on my Tek 465B's on 5mV/div isn't visible at all on a shorted 1m long probe. Dead sharp trace.

That is with two crappy Ikea LED lamps about 20cm away, in the approach window of London Heathrow and about 50 WiFi SSIDs visible  :scared:
 

Offline TheSteve

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Re: RIGOL MSO1074Z-S, 14 months after purchase
« Reply #8 on: January 14, 2016, 06:02:08 AM »
That's pretty bad. The noise on my Tek 465B's on 5mV/div isn't visible at all on a shorted 1m long probe. Dead sharp trace.

That is with two crappy Ikea LED lamps about 20cm away, in the approach window of London Heathrow and about 50 WiFi SSIDs visible  :scared:

Time for you to check out Dave's video on the subject:
http://www.eevblog.com/2014/04/10/eevblog-601-why-digital-oscilloscopes-appear-noisy/
VE7FM
 

Offline ebastler

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Re: RIGOL MSO1074Z-S, 14 months after purchase
« Reply #9 on: January 14, 2016, 06:05:56 AM »
That's pretty bad. The noise on my Tek 465B's on 5mV/div isn't visible at all on a shorted 1m long probe. Dead sharp trace.
Well, the posts above show the signal at 1mV/div. And I'm not sure whether the poster had shorted either the probe or the scope input; I think this was mostly measured with open input jacks?

As mentioned before in this thread, measuring with a 50 Ohm termination right at the input is recommended if you want to make sure that there is no environmental noise coming in, and want to assess purely the noise of the scope's input stage.
 

Offline MrSlack

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Re: RIGOL MSO1074Z-S, 14 months after purchase
« Reply #10 on: January 14, 2016, 06:37:32 AM »
TheSteve: Aware of that.

ebastler: Gotcha - didn't see the 1mV one. Not terrible then.

Agreed.
 

Offline blueskull

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Re: RIGOL MSO1074Z-S, 14 months after purchase
« Reply #11 on: January 14, 2016, 09:28:04 AM »
Attached is a noise screenshot of DS6104, tested by RigolNA tech support.

Looks very like when your scope is okay.

When your scope looks noisy, it should be some noise picking up.

Do a quick EMI measurement if you have a known calibrated high frequency (>500MHz) scope or a spectrum analyzer, using the same probe you use everyday.

If you can not spot any radiation source, try turn off everything in you lab and see if the problem shows again or not.

The last resort: ship it to Rigol and let them do their job.
SIGSEGV is inevitable if you try to talk more than you know. If I say gibberish, keep in mind that my license plate is SIGSEGV.
 

Offline CustomEngineerer

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Re: RIGOL MSO1074Z-S, 14 months after purchase
« Reply #12 on: January 14, 2016, 11:36:52 AM »
I was referring to probe plugged into scope with probe end not connected to anything (full on antenna mode). I was just mentioning because its not necessary for other electrical equipment to be turned on for it to be emitting noise that can be picked up.
 

Offline smgvbest

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Re: RIGOL MSO1074Z-S, 14 months after purchase
« Reply #13 on: January 14, 2016, 02:35:51 PM »
That's pretty bad. The noise on my Tek 465B's on 5mV/div isn't visible at all on a shorted 1m long probe. Dead sharp trace.

That is with two crappy Ikea LED lamps about 20cm away, in the approach window of London Heathrow and about 50 WiFi SSIDs visible  :scared:

Dave did a video about why you would not see this on a analog scope.  the 465B is a analog scope so not seeing on that scope is not a surprise.
Sandra
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Offline tautech

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Online Fungus

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Re: RIGOL MSO1074Z-S, 14 months after purchase
« Reply #15 on: January 14, 2016, 06:28:29 PM »
Thanks, I noticed that today. For some reason I was convinced that it was much better some times ago.

Have you got any new lamps in that time? A new PC?

Rigol are correct though. 0.5mV of noise isn't anything to worry about (on a budget scope).
 

Offline prasimix

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Re: RIGOL MSO1074Z-S, 14 months after purchase
« Reply #16 on: January 17, 2016, 01:58:15 AM »
Thanks everyone for your inputs. Dave's video helps a lot. So far I can concluded that scope is working as expected. Only that remains to some extent strange is how self-calibration each time "improve" something.
 

Offline ice595

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Re: RIGOL MSO1074Z-S, 14 months after purchase
« Reply #17 on: January 17, 2016, 06:57:17 AM »
Same thing with my DS1054Z, it seems like its picking up some periodic noise signal on all 4 channels when it on the 1mv/div range (some channels are worst than the other).
would be interesting to see where the noise is coming from ???
 


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