I tried to repeat KungFuJosh‘s Measurements but I discovered a strange behavior on my brand new scope. I can not change the gain of channel 1, it always switches back to 20 mV after 2 seconds. All other channels work as expected.
Is this a hidden feature or a failure?
![Confused :-//](https://www.eevblog.com/forum/Smileys/default/confused0024.gif.pagespeed.ce.5xOqKkq0Co.gif)
Any hint or advice from you? Has anyone else the same problem?
Latest firmware and self calibration are done.
Edit: it seems that channel 1 tries to get the signal „full screen“ as with Auto Setup.
I tried it with the probe compensation terminal, after changing Ch1 to 1 volt (or something else) it switches immediately back to 500 mV (with the provided probes). Is there an automatic gain control?
btw, channel 2-4 have the same noise level as kungfujosh‘s scope.