Siglent SDS-1202X-e waveform issues - Page 1
Forum section: electronics / testgear

author: JiaRen
author_rank: Contributor
timestamp: December 03, 2022, 04:55:43 am
content: So recently I received a Siglent scope as a gift, it has been reported to be working just fine. When i tried to use it and hooked up to it's internal square wave generator, the waveform looked out of place. Even the compensation screw on the probe is not working.Even if I probed my DAC that is outputing a 1khz sinewave, it also looked messy. I asked my friends that is using the same model and they stated that it is weird. One of them pointed out that it looks like its oscillating on the square wave. I tried everything, self calibration, updated the firmware to the latest on the siglent website. I seem to ran out of options to address this issue.

author: bdunham7
author_rank: Super Contributor
timestamp: December 03, 2022, 05:53:18 am
content: Try this:1) turn scope on2) press "Default" button3) connect CH1 probe to the calibrator output4) press "AUTO SETUP"

author: JiaRen
author_rank: Contributor
timestamp: December 03, 2022, 05:59:35 am
content: Tried that a lot of times already, still no change

author: JiaRen
author_rank: Contributor
timestamp: December 03, 2022, 07:00:48 am
content: I played the unit abit more and I put the memory depth to 140k, and it did an okay square wave but not clean. as soon as i go to other bit depth, the square wave is noisy. THe thing that concerned me is the frequency, it doesnt say F = 1.000000kHz but instead F > few mhz

author: tautech
author_rank: Super Contributor
timestamp: December 03, 2022, 08:37:47 am
content: Quote from: JiaRen on December 03, 2022, 07:00:48 amSet to max and ensure the trigger level indicator is within the amplitude of the waveform.

author: tautech
author_rank: Super Contributor
timestamp: December 03, 2022, 09:25:42 am
content: BTW, If you really want a full rundown on what this scope can do start here when member CharlotteSwiss orders hers:https://www.eevblog.com/forum/beginners/what-an-oscilloscope-recommended-for-a-woman-passionate-about-electronics/msg3104228/#msg3104228

author: JiaRen
author_rank: Contributor
timestamp: December 03, 2022, 09:55:22 am
content: Already, initially I already did it like that, but the wave would be like this. For some reason I injected a sine wave and it would appear as square wave

author: tautech
author_rank: Super Contributor
timestamp: December 03, 2022, 10:05:26 am
content: Stop, take a breath.You are connected to the probe compensation waveform, it is 1kHz at 3VSet the scope to display it with the entire waveform within the borders of the display.Then insert a FAT32 formatted USB stick of 8GB max size and press Print to capture the screenshot.Add the png screenshot into Attachments and other options so we can better see the scope settings.Be sure to have the trigger level set within the amplitude of the waveform and the easy way to do that is press the trigger level encoder which will set the level automatically to 50%.

author: tautech
author_rank: Super Contributor
timestamp: December 03, 2022, 10:24:34 am
content: Below is SDS1104X-E, the 4ch brother or SDS1202X-E. The menus, display and info tabs are very similar to 2ch X-E. Here I use 10X probe and set the input attenuation to match in the channel menu.All my settings you need match to have the same display.

author: Kean
author_rank: Unknown
timestamp: December 03, 2022, 11:15:26 am
content: Quote from: JiaRen on December 03, 2022, 09:55:22 amChannel is set to 1x and 50mV/div. You aren't going to see a full 3V signal like that.It looks like you are using a P6100 probe. Is it set for 1x or 10x? Do you know the probe is good?

author: JiaRen
author_rank: Contributor
timestamp: December 03, 2022, 11:17:05 am
content: I see, so I can just auto setup, set the time division then take a screenshot for you?

author: JiaRen
author_rank: Contributor
timestamp: December 03, 2022, 11:20:01 am
content: It’s set on 1x, initially thought it’s the probes fault. I guess it’s user error now.

author: Kean
author_rank: Unknown
timestamp: December 03, 2022, 11:29:15 am
content: Quote from: JiaRen on December 03, 2022, 11:20:01 amJust make sure the channel is set the same as the switch on the probe, otherwise voltages won't be correct.Auto setup should still be able to show the waveform, and you shouldn't have to adjust voltage or timebase to see the signal.If you have another probe, you might also want to try swapping them to see if that makes any difference.

author: JiaRen
author_rank: Contributor
timestamp: December 03, 2022, 12:02:13 pm
content: I dont know what is going on, when I pressed autosetup, nothing will come up. Only when I start touching the voltage division and the time division, the wave would only appear. So when I replicate your settings, nothing appears.

author: JiaRen
author_rank: Contributor
timestamp: December 03, 2022, 12:06:00 pm
content: Both probes same thing, auto setup wont show the waveform until i touch the voltage and time division. the 1x and 10x are set correctly.

author: JiaRen
author_rank: Contributor
timestamp: December 04, 2022, 04:04:20 am
content: My friend that sent me the gift said that the Main board must have been damaged during shipment. Best bet now is to get a replacement board from siglent.

author: tautech
author_rank: Super Contributor
timestamp: December 04, 2022, 04:43:50 am
content: Ok so have you checked channel 2 ?You will need to reassign the trigger to it too so to get a stable waveform.

author: JiaRen
author_rank: Contributor
timestamp: December 04, 2022, 04:51:01 am
content: yep, same issue. Set the trigger already aswell.

author: tautech
author_rank: Super Contributor
timestamp: December 04, 2022, 05:06:38 am
content: Have you swapped probes ?Just a piece of wire from the probe compensation terminal into the channel input should display the correct waveform with a 1V/div and 500us/div.Is there any sign that the input BNC's have suffered an impact ?

author: JiaRen
author_rank: Contributor
timestamp: December 04, 2022, 05:11:56 am
content: Yep, swapped probes, but no havent tried a piece of wire into the BNC, I'll try that.THe BNC connector has no sign of impact, so it was weird.

author: tautech
author_rank: Super Contributor
timestamp: December 04, 2022, 05:29:13 am
content: Quote from: JiaRen on December 04, 2022, 05:11:56 amP6100 probes right ?Used in 1x or 10x mode ?In 1x mode the compensation trimmer has zero effect, only in 10x mode.....but we need a scope to properly display a compensation waveform.

author: JiaRen
author_rank: Contributor
timestamp: December 04, 2022, 06:30:08 am
content: Yep, P6100, it was in 1x mode. Here this is the pic for the piece of wire going into the inputs from the compensation terminal

author: tautech
author_rank: Super Contributor
timestamp: December 04, 2022, 08:13:21 am
content: Quote from: JiaRen on December 04, 2022, 06:30:08 amLet me contact Siglent tomorrow and see if they have any comments as to what to check/do next.It seems unusual that it would display a corrupted waveform at the wrong settings and nothing at the right ones.You've done a Default, yes or no ?

author: JiaRen
author_rank: Contributor
timestamp: December 04, 2022, 08:37:27 am
content: Yep, I've hit default. Although this is my first oscilloscope, I have operated other scopes before at my work place. I instantly know something is wrong if the wave looked like that, one more comment is that when I checked a 1khz sinewave, it would appear as a square wave aswell. So, now im completely out of options.Then, ill wait on what to do next. Thanks.

author: rf-loop
author_rank: Super Contributor
timestamp: December 04, 2022, 10:29:02 am
content: Please tell oscilloscope FW version and HW version etc info from oscilloscope Info screen.1.Do factory default: Push Save/Recall function key, then select Recall menu and select Type: "Factory Default" and then "Press to recall".And pleasedo not now hit Autoset button or Default button at all now in or between any next steps!In your first message you tell you have done Selfcal. We need be sure it have done right way.2.So please do it again (after 30minute warm up).Be sure thatNOTHINGis connected to oscilloscope any inputs. Just open and empty BNC connectors.Let Selfcal run without touching scope inputs. Just follow it running to 100% and after it is ready and OK, push Run/Stop button.(if it stuck before 100%,note it and do not continue any next steps, it is then waste of time)Just for repeat that make sure it is stored in the "backbone": Please do not now use Autoset or Deafault at all in or between any next steps! : D3.Insert USB flash (for images)Push then "Print" button for image to USB. (yes I want see also this image)Based to your previous messages looks like you do not have any reliable signal generator. If you have please tell if you have, and if you also have then BNC cable.(Also I do not trust your probes at all at this time.)But before it, some easy "desert class" tests without any extra instruments or accessories like probes etc.4.Take around 15-20cm suitable wire what other end can insert to CH1 input BNC center contact only (without damage it) but what make good reliable contact.Because there is now factory defaults in use we know exactly what all settings are now.Do not change anything but said things.Change nowonlythese: Vertical: select 100mV/div and Horizontal: set 10ms/divKeep other stripped end of wire in your hand.Push "Print" button for image to USB.5.ChangeonlyVertical: 200mV/divKeep other end of fire in your handPush "Print" button for image to USB.6.ChangeonlyVertical: 2V/divKeep other end of fire in your handPush "Print" button for image to USB.7.ChangeonlySet Vertical 1V/div and Horizontal scale to 10ms/div and adjust Trigger level to +1.5VConnect this wire from CH1 center to probe calibration pulse output "1kHz" (upper connector). Be sure wire do not short circuit to GND.Push "Print" button for image to USB.Show these images.

author: JiaRen
author_rank: Contributor
timestamp: December 04, 2022, 10:44:28 am
content: The Software version is 1.3.26, the hardware version is 0c-01. I'll update on the rest later.

author: JiaRen
author_rank: Contributor
timestamp: December 04, 2022, 12:05:11 pm
content: So these are the pictures you requested3.4.5.6.7.

author: rf-loop
author_rank: Super Contributor
timestamp: December 04, 2022, 02:00:50 pm
content: Quote from: JiaRen on December 04, 2022, 12:05:11 pmSomething is broken, it is now quite clear.Please can you do all again but now only for CH2.In my last isntructons but jump over step 2.Before step 3 shut off CH1 and Open CH2.Select Trigger source CH2.Other things just as same as before and this piece of wire things now of course CH2.If there are significant differences compared to the previous ones, show pictures of them.BTW, it looks weird that even with your "wire in hand" test traces are all only positive related to GND. This is weird.And image 1. After selfcal and BNC open 1V/div. This extremely "fat" trace show that something is really wrong.Also in your all previous images I can not see any negative signals, all are in positive side.In oscilloscope there is 3 voltage bands. I, II and III. 100mV/div is in this band I. (Band I = 0.5mV - 100mV, Band II = 102mV - 1V, Band III is 1.02V - 10V/div)(this is why I ask different settings, all these use different V band)Then please do also this.Set just factory defaults.Inputs = Nothing connected. Just empty BNC.After then turn also CH2 on.After then adjust CH2 to 500μV/div and CH1 also for 500μV/divDo not adjust vertical position, leave it just center as it is.Show image.

author: JiaRen
author_rank: Contributor
timestamp: December 04, 2022, 02:59:37 pm
content: Here is the pic, andd for some reason i got shocked by the ground terminal, pulled out my test pen and this isnt suppose to happen no?3.4.5.6.7.Reset, both channel.Ground, test penEDIT: Changed the power cable, fixed the ground but the wave is still the same. Even initially, none of this getting shocked thing is happening, dont know why it suddenly appeared. Or not I would have been shocked even when im using my PC.

author: rf-loop
author_rank: Super Contributor
timestamp: December 04, 2022, 03:43:04 pm
content: First these safety things.Your scope must be connected to mains using protective ground!!!!!!!! (3 terminal connection)If your power is connected right way, it is impossible that GND have any this kind of voltage level.There must be L, N and PE (Protective Earth (PE) what is also internally connected to oscilloscope all GND, whole internal metal box is connected tp PE )(GND)))!This is mandatory for safety. As also told in user manual.Never use oscilloscope so that power is connected to 2 terminal socket.Based to your all images now, looks like there is hardware failure in your scope.I have some things that I would suspect and that I would check inside the oscilloscope, but all of them also require sufficient skills and measuring equipment to do them.But before anything else. Check the connection of the oscilloscope to the mains, that it is correct. PE must be connected, and its PE line must also be in order.

author: JiaRen
author_rank: Contributor
timestamp: December 04, 2022, 03:48:43 pm
content: Yes, its all grounded, I never use ungrounded power cables and our mains ground are also fine. I even checked the continuity of the power cable, but it is fine, and the unit's ground to the IEC ground prong, it is totally fine aswell.

author: rf-loop
author_rank: Super Contributor
timestamp: December 04, 2022, 04:36:23 pm
content: Quote from: JiaRen on December 04, 2022, 03:48:43 pmBut your test chisel show light. If PE is ok it really do not.Somewhere PE is broken, inside scope, inside mains connector or somewhere. (hard to believe your room have some extreme RF field)This kind of test pen/chisel is very unreliable in many ways.I think in your country there is Plug type G. So you can not turn it 180 degree and look if test pen light turns off.Do you have multimeter.If you have, check oscilloscope BNC etc GND have 0 ohm to plug PE connector.Then in AC voltage range measure voltage between wall socket Right and Left connector (usually L is connected to Right and N is connected to left in socket in thgis kind of socket you have there). You must see normal mains voltage.Then measure voltage between socket Right connector to PE. It must display same voltage. Then Left connector to PE connector, It have usually very low near zero voltage or just zero (depending how it is connected and load in other parts in house power lines what can rise N wire voltage level relative to PE).Then PE connector voltage to Real Ground and Earth (example metal water pipe etc) need be very near zero.I have seen so many times wrong installations and then much more eaxample broken PE (wire broken, loose contact and so on... all what can imagine and bit more. I have tens of years experience. )Are there any signs than someone have open this scope before. Broken seal, or other signs or some marks on the screws. If someone have opened it, it is not first time someone forget PE wire connecting. (with multimeter or what ever method you can test there is direct contact from scope BNC GND to power terminal PE pin. It must be 0 ohm.)

author: JiaRen
author_rank: Contributor
timestamp: December 04, 2022, 05:38:57 pm
content: I tested all of the above, Chassis ground to IEC ground prong and everything seems fine. Before I change the power cable, I did check the voltage out of the ground on the chassis terminal and BNC, it was like 52v AC out, referenced to one of the ground in one of my amplifier I’m working with. After changing it, went to 0.2v, all continuity on all grounds no issues so it is earthed. No, there is no sign of someone opened it, except I went ahead and open it up to check for loose ground or screws, nothing in there, no burn marks no anything.It is Still bothering me why suddenly there is 52v AC out of the ground terminal. Also there was no DC out so is it psu leaking into ground?

author: JiaRen
author_rank: Contributor
timestamp: December 05, 2022, 01:09:14 pm
content: Contacted siglent and they told me to send them images and videos relating to it, and they finalised that the main board is having issues and best solution is to get a new board from them. Also my scope is the early model, so it is the BA serial number ones.

author: tautech
author_rank: Super Contributor
timestamp: December 05, 2022, 04:35:17 pm
content: Quote from: JiaRen on December 05, 2022, 01:09:14 pmHQ has studied this thread too and they offer the same advice.Good luck with the repair.

author: JiaRen
author_rank: Contributor
timestamp: December 05, 2022, 05:33:58 pm
content: Thanks, Tmr I’ll put an order from siglent for a replacement board. Since at the end it’s way cheaper than getting a new one.

author: JiaRen
author_rank: Contributor
timestamp: January 03, 2023, 07:32:09 am
content: Just for an update, I recently received the replacement board from siglent and installed it. There is nothing wrong with it now, proper proper stuff that is supposed to be shown on the screen now. Thanks for the help you guys