Not exactly what I needed but valuable anyway.
Turns out the problem was in the time base, a plug-in unit that was not part of the mainframe manual. I had to order that manual separately to make a diagnosis. Even so, I now have a schematics for any future problems with my scope, so I'm happy with this purchase. I got it sooner than expected and it's in good condition for it's age.
Bestätigter Kauf: JaArtikelzustand: Gebraucht