K8031: Some questions and remarks

I just build the K8031 kit (single channel PC Oscilloscope). It works like a charm. Thanks Velleman! :smiley:

However, I have some questions and remarks.

  1. I missed the 2 metal screws to fix the cabinet parts together in the kit.

  2. The help is not consistent with reality: in the “view” menu there is no “dot join” as described in the help (I assume the dot join is always on, which is reasonable I think).

  3. During calibration (alignment of CV1 and CV2) I did use the timebase speed where the K8031 software started in (1 ms/div). The manual does not mention which speed to use. I assume this is Ok?

An extra question just popped up:

Why is D16 between the input power and the earth (if I can believe the circuit diagram), preventing (together with FS1) a wrong polarity of the input power? Doing this, FS1 blows when the input power has wrong polarity.

It would have been better (to my humble opinion) to use the same circuit as e.g. in the K8048 kit, where the diode is in series with the input power. Acting this way, FS1 does not blow when input polarity is reversed (only an extra 0.7V voltage drop in the power connection will be there, but with 9V input voltage this is no problem), the kit just does not work.