Here two images.This new power supply in picture have also SMD components on the solder side (not in picture)
These both need now more deep investigations.
(these have lot of small changes after older (many) versions.
PCB layout, routing and some componets are changed.
They have try do it better - but something is now wrong in my opinion.
It is even possible that secret is in some components specifications.
Parasitic osc...... EDIT/ADD:
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Owon have holiday 7th to 17th Feb due to Spring Festiwal time.
(whole China is more or less on the holiday) and after holiday, no one know who workers return back (hehe) from holiday and so or so but after holiday all services are heavy loaded, rush and queyed....
Disclaimer: This next all is now my unofficial opinion!
After some talking with Owon about some findings (in scope internals) I believe there is coming some, perhaps very simple, solution but not just immediately. There is not just one problem... it is perhaps group of problems perhaps related to some components parameters and perhaps also PCB design (This power supply and adapter card is very new version if looks also used components) With very fast rising edges there need handle tens and hudreds of megaherz freq components in single simple 50kHz switch mode regulator. Now something have changed and...
This is only example, NOT related to this case.
I remember once in history some fun (and expensive)... there was one case... all works in lab very nice... in proto.
One proto PCB inductor was take from "lab test and evaluating component box" but it have wanted inductance etc.. all was fully tested and exactly ok.
Then later someone buy these "looks like" inductors, same inductance and so on...
All was then wrong... extreme heat... components burn... it was like spread spectrum VHF transmitter for EW... one simple power supply.
Before solution and repair it need take extreme care about probing methods so that this partially common mode noise do not pollute signal under test or it do not disturb device under test. Inside scope it do not (significantly) pollute internal signal pathway from BNC input to ADC.
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Also note: If you have OLD version service manual or other OLD material how to open oscilloscope.
It have changed. If you try pull power button out before opening case... DO NOT. It do not come out without damage.
Push it fully inside same time carefully opening bac cover.