It's not oscillating at 50MHz. Look at the waveform, with the big spike in the middle. That's a spike at some lower frequency, wider than the screen, followed by ringing. Need to zoom out the time base some more to see the period of the big spikes. It's no higher than 4 MHZ (the screen is 12 units wide) and possibly much lower. (Assuming that M:20ns on the display means 20ns/grid division. The manual is a bit hazy on that part of the UI.)[1]

The power regulator IC mentioned is normally run at 500KHz. There's a reasonable chance that this is the power regulator spike not being damped out. Easy enough to check with a scope handy.

[1] https://fotronic.asset.akeneo.cloud/pdfs/media/owon_hds242s_...

>And "leared" -- the (unintentional?) pun made me click.

I assume it's a reference to the "Quality Learing Center" in Minnesota, one of the questionable daycares at the center of the alleged Somali daycare fraud scandal. Ever since some of the expose videos about it came out it's become a meme to say "lear" instead of "learn".

Cannot it be a noise from imperfect switching? The switching occurs at lower frequency, and the noise is high frequency.

I guess he also believes that 50 MHz or so signals can be measured reliably on a 40 MHz (on paper at least) scope.