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BarcoData Scan Fail (trying to diagnose)

Discussion in 'Projectors, Screens & Video Processors' started by Cmwmjt, Jun 20, 2004.

  1. Cmwmjt

    Cmwmjt
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    Hi, just scored an old barcodata CRT projector off a friend for free, apparently according to him it had an issue with its powersupply.

    I've had a look at the crt's they look pretty good, no evidence of burns.

    Now the problem, it powers up, I get a high pitched pulsing sound, for a few seconds, the fans come on, and I can see a browny glow coming from the back of the CRT"s where they connect to the rest of the circuit.

    When I hookup a video source I get a green LED, I have 6 amber LEDS, only 5 of the 6 light up, the one of the top right hand side fails to light, I haven't determined if it's a dead LED or not yet.

    But I do get the red one, which i've learnt indicates a scan fail, which is normally related to power supply problems?

    I just waiting on my friend to drop off the controller that plugs into the back, but I doubt this would be the issue.

    CRT tech is all quite new to me, so i'm finding this exciting working inside one, as i've never touched one before.
     
  2. Cmwmjt

    Cmwmjt
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    I removed a board with a large heatsink at the bottom, it ran the length of the board, and the RED LED disappeared. No lighting in the CRT, but as I said the red led went off.

    This is interesting, question what board is this?
     
  3. Cmwmjt

    Cmwmjt
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    Ok, at the rear of the projector is the flyback transformer or whatever it's called, it has a 34.7kV sticker on it

    Now it has two red insulated wires coming out, one disappearing into the chassis. And another with a fork end, supposed to be attached and held in place with a screw to a metal fitting.

    Now I noticed that the screw was loose and this connector was connected to nothing,

    now if memory serves correct, thats a High voltage line, but if it came loose, it would've been arcing, and even flashed over inside the transformer, killing it?

    Meaning that my problem would be a dead flyback transformer from an internal voltage flash?
     
  4. Cmwmjt

    Cmwmjt
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    Ok, I removed the last board where the HV line went into, the unit has a metal shield around it, switched the PJ on quickly, the transformer pulsed a few more time, and the amber which didn't light up, light up a couple of times and went off.
     
  5. Cmwmjt

    Cmwmjt
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    Any ideas? This is keeping me up late trying to figure out.
     
  6. Cmwmjt

    Cmwmjt
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    OK the EHT is the board with the large metal heatsink / shield. It has the flyback transformer which attaches to the voltage tripler which goes to a box which distributes to the CRT's ?

    As stated, I found the wire going from here to the tripler disconnected, meaning there must've been an internal flash over inside, damaging the flyback.

    Meaning, i'd need a new flyback-------but the more I look at this board, the more I think, MY GOD the soldering is shocking! I mean absolutely shocking!>

    And why has no body replied to my thread?
     
  7. ShinObiWAN

    ShinObiWAN
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    No one has replied because we all have no idea what you are talking about.

    Seriously though, there is possibly only one man on here can sort your problems out and thats Roland. He's a busy person but he *may* be able to give you advice and sort you out with new parts.
     
  8. Cmwmjt

    Cmwmjt
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    hehehe, ok I think what I wrote may be a little confusing. Sorry, I'm reading, tinkering and updating with me progress as I do it, and learning each time.

    Also my mistake, thought everyone here was electronically cluey.

    Pretty much, I think the problem is related to a dead flyback transformer, but I'm not 100% sure, seems like the most likely reason why. Occured because the line frm the flyback to the voltage quadrupler was unconnected, causing an internal flash over.
     

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