I bought a Philips PM 3253 oscilloscope (and got it working thanks to Electrical Engineering stackexchange, thanks for that).
However, I have a new problem. I probe to the calibration output which gives 2 KHz, 600 mV.
Initially, 0.2 V/div is selected (see yellow circle below), multiplied by 3 boxes = 0.6 V (is ok). See [1
Also when I change anything else nothing changes unless I press the Erase button. I'm sure it worked before and tried a lot of switches/buttons, but it is probably a combination.
Do you know how to change the electron beam immediately without having to press the Erase button every time?
Update: After testing a lot, now changes are more or less automatic. I think the electron beam is really old, and I have to very delicately set the Intens button .... if it is too low, it will not show anything, if it is too high, the old lines will remain (even after removing the probe). To make it more tricky, after the signal change, a bit more Intens is needed, so I have to move that dial a lot (or press the Erase button). I wonder how many problems I will get when looking at a changing signal.