February 22, 2010
about 2 years ago
I just received two more. That makes three otherwise junk-bound old scopes converted to a cool item and two board to continue experiments. It must be a couple years ago I asked the software author for a special version to slow down the display drawing rate via a numerical command and received it (thank you!), and am still working on doing the clock with an electromagnetic display. As many know, they are slow and require power amplifiers with current feedback to drive the inductive load of the deflection coil, but there is nothing like a TV set or computer monitor conversion because of the nice large screen. The black and white TV sets are the easiest to work with because of no convergence issues, but at this point I can see that I have to rewind the yoke to lower its inductance to 1mH or less for the speed. That is the state of affairs. Volume 22 of the MIT radiation laboratory series (displays) shows how to wind a yoke of various types, perhaps a lost art. “the secret life of XY monitors” online provides amplifier schematics. So, not it is not done yet but I am getting closer and of course learning far more than I had ever expected. Please keep supplying these boards!
With a 500KHz Horizontal amp, the answer is “maybe”. Can you use one of the vertical channels as an H input?
The only way to find out is to try it.
“Without blanking: http://ragelse.com/i/fOb72Nh With blanking connected: http://ragelse.com/i/SqS82Nh ” one thing annoying is the polarity of the blanking. In some cases it needs to be inverted. This means, not logically inverted, but electically inverted. In other words, the states from theboard are 0 and +3.3V. But a -3.3V(or whatever) is needed to get blanking on some scopes.
The Z axis of a scope, if DC-coupled, is meant to be blanked by a voltage below zero and intensified by a voltage above zero. So, you need a negative supply rail and an inverting amp. A transistor or two should do.
A comment on the image with no blanking: the deflection amplifier speed on that scope might be a bit slow.
This board requires a fast scope, it is unfortunate but at very least 2MHz. If the DAC could hold for a longer time after each ‘point’ was plotted, the slower scopes can be more easily used.
I hope this kit will continue, and I hope some documentation canbe created by programmers for the firmware. I do not understand software, need everything commented. I would like to see a possibly simpler rendering using less points, that could be easier on some of the oddball scopes people are trying. Anyway i am very happy with these kits, and I hope my comments on blanking helped you.
No public wish lists :(
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