New Hantek DSO2X1X models?

[masta_k74]

Of course, buying from Aliexpress always means buying at risk.
If you want it to come from a trustworthy provider, you can use this one, for example:
https://www.mouser.de/ProductDetail/Texas-Instruments/LMH6702MA-NOPB?qs=7lkVKPoqpbZhCbCGUzyOPg%3D%3D

Now that my problems with higher memory depth and the spikes that appear later at higher sensitivity have been eliminated, I will stop soldering on the hardware, at least until new problems appear.

The last thing I did was to desolder R11 in the power supply and bridge it to raise the dual 8V "a little". (I don't have any SMD resistors at home, otherwise I would have reduced R10 a bit).

I am still puzzling over how the OpAmps could burn out although the voltage regulators are still intact. So far, I know that in case of overvoltages, the regulators go completely to short-circuit or simply absorb the overvoltage without a pulse at the output. Especially since the voltage at the input can easily be 28V. Depending on the type, even more.
The only explanation I have would be an electrolytic capacitor you used in the power supply unit that had lost a lot of capacity or whose ESR was already in the completely unusable range. In other words, an extreme ripple with the switching frequency of the power supply. The normal fixed voltage regulators cannot handle this. I have already had defective voltage regulators and subsequent electronics with a normal 50Hz transformer and bridge rectifier, with a defective filter capacitor.

[nokin]

Maybe next time I will plan linear regulator using EI transformer as usual. Simple, clean and more safety than cheap and weak switching power due to cost cutting like this.
For 5V digital LM317 /LT1084
For 8V rails dual mono LT1963 are best ideal.

Now mine is working fine but power supply quite hot, every where. 3 Schottky's diodes, transformer, pcb... Even 1000/16v x4 are warm on aluminium body.

[Russ3000]

Now mine is working fine but power supply quite hot, every where. 3 Schottky's diodes, transformer, pcb... Even 1000/16v x4 are warm on aluminium body.

All heating comes from the diodes through the copper tracks of the board. It is necessary to replace the diodes with large ones so that they themselves dissipate heat.

[nokin]

Err -3,
You can also use folders, but can't have spaces or it will fail.

Yes, that's rite 
I've restored successfully !

[masta_k74]

Maybe next time I will plan linear regulator using EI transformer as usual. Simple, clean and more safety than cheap and weak switching power due to cost cutting like this.
For 5V digital LM317 /LT1084
For 8V rails dual mono LT1963 are best ideal.

Now mine is working fine but power supply quite hot, every where. 3 Schottky's diodes, transformer, pcb... Even 1000/16v x4 are warm on aluminium body.

I have thought about it long enough now and will convert to a linear power supply. This switching power supply seems increasingly suspect to me. I have nothing against switching power supplies in principle, but the implementation here is very strange. Somehow it looks as if they couldn't develop their own power supply suitable for this device and made a makeshift 5V for it in the circuit diagram.
(Just put an additional step-down converter on the +8V) The main thing is to make it as cheap as possible. This leads to the conclusion that the quality of the components was reduced to a minimum.
Sure, you can do it that way, but I call that a botched job.
(However, I will take over the generation of the line trigger 1:1 from the original circuit diagram).

[nokin]

On my D2C10 traces are very clean but the screen waveform fresh rate quite slow even I overclocked @720MHz CPU.

[Russ3000]

A photo of a new modified power supply appeared on the Internet, everything was done correctly there, a larger diode, 3 transformer windings and + 5V stabilization.

[masta_k74]

A photo of a new modified power supply appeared on the Internet, everything was done correctly there, a larger diode, 3 transformer windings and + 5V stabilization.

Modified by Hantek or by a user? Can you possibly post a link?

[DavidAlfa]

Modified by Hantek or by a user? Can you possibly post a link?

Nah, it seems they've replaced it at production. Stolen from 4pda 

[masta_k74]

The primary side has also been revised. There is now a MosFet in the primary part of the power supply. It seems that there were problems with the old one. So I think my plan to convert to a linear power supply is not nonsense in general.

[DavidAlfa]

I don't think so.
There's no single case of PSU failure, just people hyping around about the heat.
I had a lot of noise when I bought it, tried a lot of stuff, nothing made a noticeable difference.
Except...wait for it... Properly grounding the scope!
My wall socket used an old weird type with 3 pins (Socket J?), earth couldn't be connected with Shucko plugs.
Had a crazy amount of ringing, completely gone after installing a proper socket and throwing that trash away (Not the scope lol).
People have added 5kg to the scope by adding crazy toroidal transformers and huge capacitors, with little to no difference.

[arturmariojr]

I replaced the switching power supply by a linear one.

One monstrous two polo filter taken from a Plasma TV board;
So, one 3A transformer, 6+6VAC transformer (not toroidal):
And circuits:
- 5Vdc source: 1x bridge rectifier, 2x 10000uF 25V caps, 1x LD1085 - V36 and two resistors (120r and 50r), a 10uF cap
- +8 -8Vdc unregulated power supply: bridge rectfier, 2x4700uf x 25V capacitors plus the TR signal components taken from 8VAC transformer.

The scope gain weight and stabilit for use too.

Noise has gone but the wave is not stable. I think small noise makes the zero crossing sensing craizy.

[nokin]

Yeah Mine is exactly this version. Pcb is printed "batch 072022".
But it still hot. I added 5v mini fan which flows directly to power board, it's quite ok.
Traces are super clean. No spike anymore at any div. 

[Russ3000]

Modified by Hantek or by a user? Can you possibly post a link?

Nah, it seems they've replaced it at production. Stolen from 4pda 

Photographed with a lighter? 
It makes sense to redo the power if it is possible to buy a suitable transformer. For the analog part, you do not need to make a stabilizer, just 2 windings with a midpoint, a diode bridge and 2 capacitors 2200 x 16V are enough. To power the digital part, any 5V stabilizer from a separate winding of the transformer is suitable, there are still their switching stabilizers. The main thing is to untie the ground wires of analog and digital power, they should meet only at the ADC chip. It will be right.

[nokin]

I wonder about noise vs power supply board
Mine was bought near 1 month ago, directly from taobao
Mainboard revision like all of yours, 2D15 dated code 2021
So if you improve or replace new better power board with same mainboard like me maybe you have same better result like me, but no any improvement here.

Now Im just only disappointed about waveform screen refresh rate

[DavidAlfa]

If you check carefully, the noise is mostly 2 LSB with some 3 LSB peaks.
So, if the ADC range is 0-255 and we have a "127" input signal, the noise would be doing 127,128,126,127,128,129,126...
I wouldn't expect anything better from a cheap scope running 1GSps ADC in a 2-layer pcb.
Perhabs wrapping the whole board in copper foil and grouding it would help.

[nokin]

In fact whole board is shielded by frame but more pcb's layers should help to get the best grounding.
 @DavidAlfa : how to get or show the number 1GSa/s ? This number is randomly even at 50us and 1 channel selected.

[Russ3000]

If you check carefully, the noise is mostly 2 LSB with some 3 LSB peaks.
So, if the ADC range is 0-255 and we have a "127" input signal, the noise would be doing 127,128,126,127,128,129,126...
I wouldn't expect anything better from a cheap scope running 1GSps ADC in a 2-layer pcb.
Perhabs wrapping the whole board in copper foil and grouding it would help.

Before reworking the power supply, it looked like this to me, it's a pity the picture was not preserved.

[DavidAlfa]

how to get or show the number 1GSa/s ? This number is randomly even at 50us and 1 channel selected.

It depends on the time division used.
1Gsps can be only used with 4K memory depth.
1ns/a sample * 4000 = 4us, that's the max time it can capture.
Divide that by 12 divisions and you get 333ns/div.
I xan't remember, but probably only uses 1GSps in 200ns/div and lower.

[masta_k74]

@Russ3000

So slowly it went in that direction with me, although it wasn't quite that bad yet. It only appeared with me after some time. All in all, after about 40 - 60 hours of operation. That's why I installed the ceramic capacitors and the ferrite rings. That also helped for the time being. My guess is that this is the beginning of the end for the filter capacitors. If I touch the power supply again, I'll put a linear one in there and this aberration will be removed.

[nokin]

@DavidAlfa
I've attached some pics. Look like these are less noise than yours.

@Russ : it's quite terrible 

[Russ3000]

@Russ3000

So slowly it went in that direction with me, although it wasn't quite that bad yet. It only appeared with me after some time. All in all, after about 40 - 60 hours of operation. That's why I installed the ceramic capacitors and the ferrite rings. That also helped for the time being. My guess is that this is the beginning of the end for the filter capacitors. If I touch the power supply again, I'll put a linear one in there and this aberration will be removed.

The installation of 3 MBR10100 diodes in the TO220 package helped me, it immediately became cool and the needles in the picture were completely gone. I was very surprised.

[masta_k74]

That would be a possibility, of course, but I have had so many defective switch-mode power supplies on my desk that nothing convinces me to use a switch-mode power supply that has been slimmed down so much for cost reasons that its durability is guaranteed to suffer. It doesn't matter to me in the least how heavy the device is or whether I "waste" 2W or 12W during operation. Reliability and low interference are far more important to me. (Even if you will probably never get this device completely free of interference).

[Russ3000]

If you do not save on details, you can make a reliable power supply. I myself developed power supplies for technological equipment and passed various certifications, it turned out very reliably and quietly, I can’t imagine a stabilized power supply for 12V 100A with a transformer. Normally, the input voltage is ～90-260V, transformer units cannot do this.

[DavidAlfa]

The installation of 3 MBR10100 diodes in the TO220 package helped me, it immediately became cool and the needles in the picture were completely gone. I was very surprised.

Diodes? I don't think so.
More like the capacitors you replaced at the same time, which are by far the most important components when filtering the spikes.