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Thread: CYGN-A

  1. #11
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    Default Actual scans of cards

    Quote Originally Posted by Greg View Post
    I was going to ask how to deal with the unavailability of the IH5012CPE Virtual Ground Analog Switch (excerpt from datasheet attached), which is used in the SPGN, but once again, they are not unavailable. Ordered a batch.

    Regarding the CYGN-A, am I correct that the component placement chart and the PCB in the attached photo are not the same circuit?
    Greg,

    Here are actual scans of the card that I just dug out of the garage.

    Ron
    Attached Thumbnails Attached Thumbnails CYGN-A-front.jpg  

    CYGN-A-back.jpg  


  2. #12
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    Instrument Grade PhotoMos relays are what I just bough to deal with a similar problem. They do not have the elegant correction scheme to deal with distortion that some of the newer chips post 1990 have, but they work for DC-audio just fine. . I use them at work.
    I grabbed 20 of these lately when they were on sale at 99 cents as they retail around 7$ each in the through hole package.

    Panasonic/NAIS AQV258 Solid State SMD Relay



    G23378 - Panasonic/NAIS AQV258 Solid State SMD Relay (goldmine-elec-products.com)

    I'll know how well they work on scaled down ILDA signals this weekend.

    These are also rated for audio:

    LH1518AAB

    Steve
    Last edited by mixedgas; 01-12-2021 at 08:49.
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    When I still could have...

  3. #13
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    notes on preparing for the CYGN-A build:

    substitute original UA741CV with UA741CN
    substitute original RC4558DN with RC4558N

    Ambiguities regarding capacitor values (attached graphic): Probably fine to go with 0.01uF and 0.033uF, but in the documentation, there is ambiguity about what these values are.

    More interestingly, I wonder why Oscillator 3 has a different value of capacitors than 1 and 2.
    Attached Thumbnails Attached Thumbnails CYGNA_cap_ambiguities.jpg  


  4. #14
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    Oscillators 1&2 were typically high max frequency oscillators and 3 had a lower max frequency. Since the CYGN-A was designed for the Mark 4 the caps were changed with the advent of the Mark 6's G-124 scanners.
    Last edited by laserist; 02-01-2021 at 05:51.
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  5. #15
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    Combining parts for the SPGN with the CYGN-A in the same ordering frenzy. See attached graphic for considerations regarding part NE536 specified in documentation vs. LF356BN seen in Ron's photo.
    Attached Thumbnails Attached Thumbnails SPGN_component_substitution.jpg  


  6. #16
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    Dogloid + SPiral GeNerator (attached image)
    Attached Thumbnails Attached Thumbnails DOGN_and_SPGN.jpg  


  7. #17
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    Quote Originally Posted by Greg View Post
    Dogloid + SPiral GeNerator (attached image)
    CYGN-B?, swept spirals, fixed rotation, variable rotation, AOM chopper, and stars too...
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  8. #18
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    I'd like to get this problem out of the way. Steve, perhaps you could help with this: I need to scale the 0 to 2.5V dogloids signal output to +-10V. The values line up exactly with the case given in the document (excerpt incl. schematic attached) but something isn't right (see attached annotated scope captures).

    Brian, The pinout format page of the SPGN documentation suggests the module exposes an interesting variety of input and output signals, which I may request your help deciphering in a couple of months when all the components arrive and the build begins. Do you have any sharable recollections for this thread regarding Carl Hannigan? Other than your earlier comments and seeing his name as the engineer of the SPGN, I don't know how and when he fit into the history of Laser Images Inc., but I guess he was an impressive person.
    Attached Thumbnails Attached Thumbnails UnipolarToBipolarVoltageProblem.jpg  

    UnipolarToBipolarVoltageFromDAC.png  


  9. #19
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    Unless I'm missing something, the 11K resistor is pulling down the 1.25 volts from VREF and offsetting your signal. Lose it. To get 10V p2p you want a 66K feedback resistor.

    Sorry I meant to get +/-10V...
    Last edited by laserist; 02-04-2021 at 15:49.
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  10. #20
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    Request for wisdom on a couple of points:

    1) Attached graphic shows the nodes involved in wiring the frequency control pots to a CYGN-A oscillator. Any advice regarding where the grounds and interconnects go?

    2) Is the rotary ganged switch labeled Spiral Select related to the SPGN?
    Attached Thumbnails Attached Thumbnails CYGN-A_frequency_pots_wiring.png  


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