Hello.
Thank you everyone for this useful thread. I've got a 2D15 and thanks to post #643 I could cross-check that I get more-or-less the same response (IMHO the most interesting is the 10 MHz squarewave). I have updated to the latest official firmware, that is 04-2021, and recalibrated the oscilloscope.
I would like to ask a comparison of what you get when channels are set to GND. In my unit, regardless of the V/div setting, CH1 is about 1/5th of division above 0V and CH2 is about 1/5th of division below 0V. See the attached pictures.
With DC coupling the offset is equally present and impacts DC readings. With AC coupling it goes away.
What kind of GND do you get on yours?
Thanks!
On mine
As it came from Hantek (20210416.00, Firmware 3200), no hacks, no firmware changes and no calibration:
CH1 is 2 5ths above 0V and CH2 is within 1 point of 0V.
The DMM function reads 3.29mV DC for CH1 and 480-500µV for CH2.
Power on for 15 minutes. Disconnect probes, then run internal calibration:
Ch1 is -1.0mVDC Ch2 is 3.05mVDC
Wait 10 minutes, run calibration again.
Ch 1 is 2.95mVDC Ch2 is -1.1mVDC
Connect probes hooked to front panel ground post. Similar offsets but nearly 500mV p-p noise.
Connect probes to 2.5000VDC reference. Set vertical to 1V/div. Internal DMM - Ch1 2.47VDC Ch2 2.52VDC. Traces are within 1 line width of each other. I let it run for several minutes. No change.