i found a cs-8010 for $55 but it says its untested. i have never owned an oscilloscope before but i know that the old dsos are not as good as old analog scopes. i couldn't find any info on this scope does anyone know if this is a combination scope or just a straight up dso. it says its un tested but the display shows a trace what is the likelihood that there is something wrong? would this be a good beginners scope?