Yes, I do, and will post shortly.Quote:
Originally Posted by glorocks
(Oops, sorry. I thought I did but only have their A-600 driver board.)
If interested, here is my version of an open-loop drive amp that I used on the GS-115 galvos back in 1977-1979 using the single uA791 op-amp driver. This could easily be modified to be a non-inverting version and/or differential balanced input version. I used 7812 abd 7912 1amp voltage regulators. The nice thing about the 791 op-amp driver was that its output was current limiting to 1 amp, bipolar and therefore protected the galvo load. I used 4 pairs of these drivers on my 1st RYGB projector. Never had a failure.
If you need to drive heavier current loads like for the GS-300 series or similar you can use the 791 as the pre-driver to an differential output using two 3055 transistor drivers in a push-pull arrangement and using + and - 24vdc supply rails on the 3055's.
Attachment 58157
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Edit: Dec 14, 2021
I found in one my old TV interviews open-loop scanner examples of the resonant frequency ringing in the General Scanning G-115 scanner I used. I clipped a few frames from the video to show as examples.
I'm fairly certain (after 41 years) the first two images show a 45Hz square wave (1st harmonic signal) with 90 degree XY phase shift, the second just slightly phase-shifted from the first.
Attachment 58558 Attachment 58559
The third image shows a 90Hz square wave (2nd harmonic) with a 90 degree XY phase shift.
Attachment 58560
I still intend to get these old scanners hooked up to a pair of u791 opamp drivers shown earlier in this post and take some videos to post here that shows the "magic" of the ringing at or near the scanner's open-loop resonant frequency.
