I've been searching all over the net for any Intron DSO-2020A documents (schematics if possible) but it seems too old to have any available although someone in an other forum said they had some in 2008. Not sure if i'd dig up the topic again...
The only thing i found is a reference to the older model here:http://www.radiomuseum.org/r/intron_storage_oscilloscope_dso.html and a picture of the one I have here :
http://www.radiomuseum.org/r/intron_digital_storage_oscilloscope_dso_2020a.html#bFun fact, the one I have has the CRT cover of the DSO-2000... I think someone tinkered with it before I got my hands on it and decided to have a laugh but since they both use the same CRT model, it doesn't surprise me that much.
Anyway, it powers up and I get the trigger led to light when tinkering with the knobs but the screen remains silent. I haven't tested it any further yet but I'm sure I'll find something bad in there.

Anyway, I'd be happy if someone could point me in the right direction for the docs. Is there a website for really old stuff ? The links provided in the previous posts don't list any Intron stuff like they don't exist. I have to say though that this scope was made in the Netherlands according to the back plate.