SCELBI o-scope

I reversed the Y axis connections and tweaked the software some more.

This picture demonstrates that one remaining issue is related to the Z Axis. First 5 characters on first line are supposed to be starburst, space, A, Z, 0 and 9.

Z Axis Issues

Z Axis Issues

Seems like hooking the Z axis to my scope with a 10x scope probe causes a lot of latency in Z axis display, due to RC delay in the Z. The lag causes a line to be displayed, to actually not show, but the next line will show. Changing the probe to 1X causes Z axis to completely not function. Could be my Tektronix 465 isn’t compatible with the SCELBI design. I’ll have to investigate both the scope and the SCELBI O-scope implementation in order to find a good fix.

2 Responses to “SCELBI o-scope”

  1. MiaM says:

    Is there even any kind of standard data on the Z input of oscilloscopes? I’ve used oscilloscopes now and then (mostly for standard measurements) since the 80’z and never came across any info about the Z input except that it modulates the intensity and in some cases maybe some kind of absoulte maximum ratings. Never seen anything about which levels actually are the ends of the linear modulation range.

    P.S. Keep up the good work, I’m impressed!

  2. Len says:


    Really nice job on this. It looks like you are making good progress. I’m looking forward to seeing readable output. Can’t wait to have one of my own!

    Hope you all have a Merry Christmas.