Siglent SDS-1202X-e waveform issues

[JiaRen]

The Software version is 1.3.26, the hardware version is 0c-01. I'll update on the rest later.

[JiaRen]

So these are the pictures you requested
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[rf-loop]

So these are the pictures you requested
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Something 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/div
Do not adjust vertical position, leave it just center as it is.

Show image.

[JiaRen]

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?
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Reset, both channel.


Ground, test pen


EDIT: 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.

[rf-loop]

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.

[JiaRen]

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.

[rf-loop]

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.

But 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.)

[JiaRen]

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?

[JiaRen]

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.

[tautech]

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.

HQ has studied this thread too and they offer the same advice.
Good luck with the repair.

[JiaRen]

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.

[JiaRen]

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