It's not practical I know, but I thought it would be fun. A 200 LED oscilloscope as a good soldering project for low speed, simple projects etc, ie: 555 projects. Easy I thought, use the LM3914 to drive the ten vertical 10 LEDS while the two 4017s to handle the twenty horizontal LEDS in a 10x20 matrix. But it's not so easy!. Can any one suggest a sensible way to convince two 4017s to step through twenty LEDS horizontally clocked by an adjustable 555 as the time base. Since 4017 count decades I wanted them to both count on the same clock input but #1 4017 to display the first ten LEDS while #2 4017 ran the second ten LEDS. Each 4017 needed to blank the other 4017. Some one with greater logic skills I'm sure could sort this. I tried #1 4017 holding reset the 4017 #2. I've tried #1 4017 blanking the #2 4017 by killing it's ground, I've even tried powering off each 4017 alternately. None of these attempts really work. Any ideas out there from minds much brighter than mine?