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Thread: Blanking Issue ( itop dac )

  1. #1
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    Default Blanking Issue ( itop dac )

    I have itop DAC ( silver star ), it was working fine with a laser projector i just sold ..now i am trying to get it to work on another projector I just built and its driving me up the wall.

    THE PROBLEM I HAVE IS NO BLANKING ! its working great apart from i cant get sodding blanking to work. I am using a viasho single 532nm laser set to + TTL Blanking ...... ( so that gives me wire with single centre core (+) and outer core either (-) or ground ?

    This set up has 30k scanners ... they have two amps and each amp has two wires ... one with red line on it other no red line. So thats X+ and X- and also Y+ and Y- . K thats seems to fine , got them wired to pins as i beleive is normal .... pins 1,2,14,15 ...now i have tried variations on pins 3,16 ( intensity) and also 6,19 ( G+ & G- ) to no avail for blanking .. i just dont understand why its not blanking ... you got any clues ?

    Somehting tells me i should try X- , Y- , pin 25 and pin 16 all connected together and wired back to both amps chassis ( as grounding )........... is that waayyyy off base ?

    PAUL
    In the beginning there was none. Then came the light - #1 UKLEM - 2007
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  2. #2
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    Default

    try this circuit, for correct differential reception.

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  3. #3
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    Default

    Dave
    I appreciate the thought .... but I have no background in electronics and the above doesnt mean a lot to me .
    Paul

    EDIT ADDITION... can anybody help translate above for me into WIRES and PINS ? ( or even explain to me what differential reception is ? is that blanking ? LOL )
    Last edited by Lasermad; 06-18-2007 at 02:32.
    In the beginning there was none. Then came the light - #1 UKLEM - 2007
    BUY UK LEGAL LASER POINTER :: NEW - Blue 460nm Laser Pointers

  4. #4
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    Ok , finally got blanking working .. ** BUT **with an issue ! so i am still doing something wrong !

    I got it working by switching to analogue , attaching centre core from blanking to pin 16 and the outer core to the metal surround of the DB25 socket . It WORKS ,i have no idea WHY but it does !

    NOW FOR THE PROBELM
    The output is very low ... for a 1 watt laser is kicking out less than 200mW ......

    This might be giving me a clue to whats wrong overall ........ i am starting to think the itop DAC is not kicking out 5 volts ,indeed on checking it with a multimeter ( digital though ) I can only get readings of 4 volts ... i dont think this is enough to activate the viasho blanking in TTL mode whereas analogue is variable votalge .

    Does any of this make sense ? are my thoughts correct ..is there major flaws in my logic ... is there other ways i can test to confirm ?

    PEG
    In the beginning there was none. Then came the light - #1 UKLEM - 2007
    BUY UK LEGAL LASER POINTER :: NEW - Blue 460nm Laser Pointers

  5. #5
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    Assuming the dac has 2.5v color channels, this is what i would try for single ended operation.

    attach pin 16 to ilda ground( pin 25), run this to the shield, connect pin 3 to the center.

    You wont get accurate voltage readings with a voltmeter - you really need a cro.
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