What would you do with my rigol DS4024 'scope - Page 1
Forum section: electronics / testgear

author: Pedro4
author_rank: Newbie
timestamp: June 15, 2025, 02:53:38 pm
content: I bought this scope in 2018 and it cost me £2678 which was a lot of money for a hobbyist. Then I was 71 years old and thought I'd set myself up for life with a really nice 'scope.However, I recently discovered it emitted a lot if RFI such that I couldn't use it to repair my friend's radio (seehttps://www.eevblog.com/forum/testgear/rigol-ds4024-generates-emi-on-vhf-fm-radio/msg5766401/#msg5766401). I sent it back to Rigol dealer and they spent 3 weeks communing with Rigol who then said, yes it is generating the complained of EMI, but it is within spec. I don't have the tools to refute that. As it's out of guarantee, all Rigol could do is replace the main board, and that would cost more than a new scope so not sensible. So, I took it back and vowed to put up with the EMI.However, now there is 0.6 divisions of broadband noise on all four channels when set to Y sensitivity of 50 mV. It is ok at lower gains. See attached photo, with comparison to my old Hitachi CRT scope. I'm thinking modern scopes have one massive multi-layer PCB that wouldn't lend itself to component-level repair. Anyway, there are no schematics, so I haven't bothered to open the DS4024.Trying to learn from this experience, I priced up a 4-channel Tektronix scope. After I had added triggering options for RS232, SPI and I2C, it came to over £9000, so that was not an option for me. So what I've done is bought a Rigol DHO1204 for £1216 and I'm going to sell it on Ebay in three years time when the guarantee runs out, and buy another one (if I'm still alive!).So my question is what should I do with the DS4024? I have a good reputation as an Ebay seller so could not put it up there without honestly declaring its faults.

author: jjoonathan
author_rank: Frequent Contributor
timestamp: June 15, 2025, 05:29:22 pm
content: Your noise comparison seems to be making the mistake of comparing noise floor across bandwidths and intensity curves. All else equal, a 600MHz instrument will capture quite a bit more noise than a 60MHz instrument by virtue of simply not being blind to it and a "digital phosphor" that lights a pixel very brightly with a single nanosecond excursion will capture the appearance of even more noise for the same reason. I don't recall the noise figure of the DS4000 being exceptional, but you put it at unnecessary disadvantage if you don't normalize for these factors.Not everyone cares as much about RFI, you aren't committing a sin by listing this on ebay and a disclosure won't drive everyone away. That said, as you have observed, competition is heating up in this segment so you will have to accept some depreciation, but that's how it goes.I had one of these Rigol DS4000 scopes a long time ago and if you are concerned about opening it up don't be, especially if you just want to modify the power supply or something. If you want to separate the mainboard from the front panel there are three hidden screws under the front panel sticker, watch for those, but that's the only tricky bit I remember. IIRC the motherboard is fed entirely from a single 12V molex cable (or maybe it was 20V) -- I had plans to make a battery-powered version but then micsig came along and released a better version of what I was planning to build so I just bought that instead, but my point is: a power supply mod is probably quite doable if you think that's the problem, but there really isn't anything wrong with selling to someone who cares less about that. Comparative advantageMy DS4000 adventure:https://goo.gl/photos/dxU3ChWUcvCMDW4N9

author: Pedro4
author_rank: Newbie
timestamp: June 17, 2025, 09:37:24 pm
content: Thanks. That was a marathon repair you did. Well done! I wouldn't try anything like that as I'm sure I would just make things worse.Good point about the bandwidth. It's actually a 350 MHz scope and I normally use it without any BW limit, so asking for trouble. On the other hand if I actually wanted to examine say a 200 MHz small amplitude signal, it would be difficult. Putting on the 20 MHz BW limit does greatly reduce the noise. Also, if I change acquisition so it averages 16 traces, noise goes away. Thing is, I don't remember it being that bad before, but perhaps I've never tried it in this way. Noise isn't on the test signal, as it is on all four channels. Possibly something has caused the scope to generate more noise internally, which it is picking up. I can't find a spec for the DS4024 for noise on Y channels.Looking at my original outlay of £2700, it amounts to £337 a year over eight years, which is not a bad hire charge for a nice scope. I'll probably just put it on Ebay with disclosure and hope for the best.

author: trukresom
author_rank: Contributor
timestamp: June 18, 2025, 09:23:29 am
content: Pedro4,Already 10 years ago I complained about the noise of my DS 4054.Perhaps you could compare this with your scope.Look here:https://www.eevblog.com/forum/testgear/rigol-ds4000-series-owners-please-tell-me-everything-you-hate-about-em_/msg646605/#msg646605(There is a mistake in my comment: CH3: 20MHz CH4: 10 MHz)

author: RoGeorge
author_rank: Super Contributor
timestamp: June 18, 2025, 09:34:21 am
content: If the low signal to observe is repetitive (while the unwanted noise is random), you can make the signal to appear more clear by setting the "Acquire" mode to "Average".Small signal on 'Acquire' mode 'Normal':Same signal with 'Acquire' mode set on 'Average' (1024 traces):Of course, this won't make the analog front end of the scope to be less noisy, but it can make the traces to look very clean.Another trick about the averaging mode, and this is only in case you also have access to a synchronous clean/strong signal (the original signal without noise), a lock-in-amplifier can be improvised from an oscilloscope on averaging mode (as in, similar functionality with that of a LIA):https://www.eevblog.com/forum/projects/oscilloscope-with-trace-averaging-as-a-lock-in-amplifier-(rigol-ds1054z)/

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 18, 2025, 01:25:08 pm
content: You can average out noise as RoGeorge already mentioned, and even increase the captured resolution of the signal in that way. You can also reduce the number of triggers (For example with hold-off time). Your scope is showing hundreds or maybe thousands of traces on top of each other, and each adds it's own noise. In single capture mode, you just have a single trace with the noise that is present in that small time frame.