A friend offered
Oscilloscope UNAOHM G4020 = BECKMAN 9020 = Voltcraft_2040
In first hours worked ok ... I saw the 0,2 V 1000Hz
and other signal in the cinescop.
But now I only see 1 or 2 dots (channel 1 or both or ch 2)
I can move the dots UP and DOWN, LEFT and RIGHT
so the screen - cinesc. is working.
I test the trigger, connect CAL 0,2V 1KHz to ch 1 or 2
and the dot go up - down, invert, etc.
A sinos. wave, I can rotate TRIG LEVEL and the dot follow
But I can't see the wave in display
Some examples of scope:
Manual and schemat. I have the French and Germany version.
Can you please provide help?