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Camera IC ...

Discussion in 'Electronic Repair' started by Arfa Daily, Sep 16, 2007.

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  1. Arfa Daily

    Arfa Daily Guest

    Anybody got any data on a VGT7616-2077 ? Particularly interested in pinouts.
    It's used in a Burle video surveillance camera, so if anyone has any
    schematics for any Burle cameras, it may appear on one of them. Can't give
    the model unfortunately as, even though there is a model / serial number
    plate on it, nothing has ever been printed or stamped on it ...

    I have tried all the usual data sheet sources without success. There's a
    couple of pages of good hits for it on Google, so it's a readily recognised
    device, but half the sites are Chinese, and unreadable even after
    translation, and the rest refer off to other sites for the data sheet, which
    then don't actually have it. Not desperate, as it's for a 'project' rather
    than a repair, but it sure would make working up the mods that I need to do
    to the camera, a lot easier with some pinning data for this chip.

    Thanks all

    Arfa
     
  2. Franc Zabkar

    Franc Zabkar Guest

    All I can find are references to VGT7616-nnnn in a 44PLCC package with
    date codes around 1988. Usbid.com says it is a Vitelic part, but other
    sites suggest it was made by VLSI Technology. My cross reference book
    lists VGC prefixes (but no VGT parts) for VLSI Tech, so I would lean
    toward the latter. I suspect the part is a field or mask programmable
    ASIC of some kind, as that was VLSI Tech's forte. The variable suffix
    would tend to support this.

    - Franc Zabkar
     
  3. Arfa Daily

    Arfa Daily Guest

    Hi Franc

    That was my first thought as well, as soon as I saw the dash number on it,
    but I was encouraged when I found plenty of references to it on the net, as
    well as others from the same series but with different dash numbers. I
    figured that maybe rather than it being an OEM-specific programmed device,
    that perhaps it was just programmed up to be a 'useful' chip. It seems to do
    most of the timing for the CCD readout process, as well as V & H sync
    generation.

    I reckon 1988 would be about right. What I am trying to do with this camera,
    is to replace a vidicon camera in a system, whose timebases are derived
    directly from pulses supplied by an external part of the system. If I can
    figure which pins are ins and which are outs, I may be able to synchronise
    the VGT chip to the external system. There are plenty of pins which have H
    rate and V rate pulses on them, so I think that it's potentially promising.
    Thanks for your interest anyway.

    Arfa
     
  4. Chris Jones

    Chris Jones Guest

    If you can find the reference frequency source for the chip (probably a
    crystal oscillator I would expect) then you could add some varactors (or
    swap it for a VCXO module) and make it tunable and then use a PLL chip like
    a 9046 to compare the VSync pulses from the camera with your external Vsync
    signal, that should get allow you to get the vertical sync to match.
    Unfortunately I think that will not necessarily get the HSync to match
    because I seem to remember that there is some difference between the even
    and odd fields, and I guess that the camera could be doing even fields when
    the external sync is doing odd fields. I suspect that it might be better
    to get a camera module with the requisite inputs already fitted, especially
    if you are not doing this for fun but expect your hours to be paid for in a
    monetary sense. If you feel like posting a photo, I'd be interested in
    looking at it, but only if is is no trouble because I'll be no help to you.

    Chris
     
  5. Arfa Daily

    Arfa Daily Guest

    Hi Chris.

    It is a 'just for fun' thing. It's actually part of a Panasonic semi pro
    (??) production console - well possibly 'domestic', but from its time, more
    sophisticated than your avaerage Joe would understand. It has such things as
    colour separation overlay (chroma key) and auto and manual vision and sound
    crossfades between sources and so on. I use it as part of my ham radio ATV
    station. One of its features is to allow an input from a black and white
    camera on it, to be used as an overlay or transparency in any colour you
    like. It's useful to overlay text of your callsign onto the shack main
    picture, when you are just accessing the local repeater to see if there is
    anyone about. If anyone comes back to you, you just hit the auto-fade
    button, and the text overlay fades down, bringing up the main shack camera
    onto the transmission.

    The camera that does this is called the 'Telop' camera, and is a 1/2"
    vidicon type. The trouble is that this kit is powered most always, so over a
    year or so, the camera tube wears out, and they are getting a bit rare now,
    so I thought I would look into using a solid state replacement, and the
    Burle came to hand. As you can imagine, the input from this camera has to be
    completely synchronised with all other video sources, so sync is stripped
    from the sources, and split into H and V sync, and then fed up to the Telop
    camera. Those pulses are then used to generate the actual timebases for the
    camera tube scan coils - that's not to synchronise line and field
    oscillators, the pulses *themselves* are processed within the Telop camera
    to produce the actual scan waveforms.

    As a next move, I might try hooking up the video output from the ss camera
    into the console, then dabbing around with the H and V pulses, via suitable
    resistors of course :) , to see if I can sync it all up in any way that
    works acceptably. It doesn't really matter if I succeed in twatting the
    camera - it was a 'surplus' one that was laying on the shelf collecting dust
    anyways. Likewise, no great problem if I twat something on the Pan, as I
    have the service manual for it, and there is nothing special in it,
    chip-wise.

    Your thoughts regarding possible ways of syncing it all up are noted, and i
    thank you for your interest.

    Arfa
     
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