Thank you all for suggestions - it worked! Indeed, after rotating both the outside (A) and the inside (B) timebase knobs a few times, and cranking up the intensity control, I did get something that resembles the sample trace:
/g/TekScopes/photo/60634/0?p=Name,,,20,1,0,0
It seems though that the trace is bit blurry, jittery/jumpy, and with a significant amount of ghosting... The same symptoms (blurry, unstable and ghosting) are present on a simple trace as well:
/g/TekScopes/photo/60634/1?p=Name,,,20,1,0,0
I suppose that I will start by trying to clean both A and B Volts/Div Attenuator Switch contacts...
