Please tell oscilloscope FW version and HW version etc info from oscilloscope Info screen.
1.
Do factory default: Push Save/Recall function key, then select Recall menu and select Type: "Factory Default" and then "Press to recall".
And please do not now hit Autoset button or Default button at all now in or between any next steps!
In your first message you tell you have done Selfcal. We need be sure it have done right way.
2.
So please do it again (after 30minute warm up).
Be sure that NOTHING is connected to oscilloscope any inputs. Just open and empty BNC connectors.
Let Selfcal run without touching scope inputs. Just follow it running to 100% and after it is ready and OK, push Run/Stop button.
(if it stuck before 100%, note it and do not continue any next steps, it is then waste of time)
Just for repeat that make sure it is stored in the "backbone": Please do not now use Autoset or Deafault at all in or between any next steps! : D
3.
Insert USB flash (for images)
Push then "Print" button for image to USB. (yes I want see also this image)
Based to your previous messages looks like you do not have any reliable signal generator. If you have please tell if you have, and if you also have then BNC cable.
(Also I do not trust your probes at all at this time.)
But before it, some easy "desert class" tests without any extra instruments or accessories like probes etc.
4.
Take around 15-20cm suitable wire what other end can insert to CH1 input BNC center contact only (without damage it) but what make good reliable contact.
Because there is now factory defaults in use we know exactly what all settings are now.
Do not change anything but said things.
Change now only these: Vertical: select 100mV/div and Horizontal: set 10ms/div
Keep other stripped end of wire in your hand.
Push "Print" button for image to USB.
5.
Change only Vertical: 200mV/div
Keep other end of fire in your hand
Push "Print" button for image to USB.
6.
Change only Vertical: 2V/div
Keep other end of fire in your hand
Push "Print" button for image to USB.
7.
Change only Set Vertical 1V/div and Horizontal scale to 10ms/div and adjust Trigger level to +1.5V
Connect this wire from CH1 center to probe calibration pulse output "1kHz" (upper connector). Be sure wire do not short circuit to GND.
Push "Print" button for image to USB.
Show these images.