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Electronics monitor Mod

Discussion in 'Modding' started by _Dan_, 5 Jun 2006.

  1. _Dan_

    _Dan_ What's a Dremel?

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    hi, well i just got a 15" flatscreen tft off ebay for £15 only fault is that the power suply is screwed. so what i wanted to know is what voltage a typical monitor runs off and if it would be possible to run it off a modded pc power suply.

    thanks Dan.

    P.s i can get photo's or any other information if it will help you in helping me out.
     
  2. agent420

    agent420 What's a Dremel?

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    I would think different companies and/or different models may have differing requirements. There's probably 5v for sure and maybe +-12 or 15. Can you get some hint by looking for regulator chips and the like? A lot of times I get lucky by reverse engineering the circuit based on component values, and if I'm really lucky the pc board has test points with the voltage identified.

    [edit]

    A picture never hurt :)
     
  3. cpemma

    cpemma Ecky thump

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    Or a brand and model number. ;)
     
  4. _Dan_

    _Dan_ What's a Dremel?

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    hi sorry should of mentioned this in the first place rite its a Packard bell ft500

    rite i got the camera out and tryed to take some photo's but its a not so great camera so when i tried to zoom in close or get a close up photo it wouldnt focus i did manage to get these thow

    [​IMG]
    this one is off the driver board i checked out all the components and the only voltage related informatation i got was a few of the small transistors had 16V on them
    [​IMG]
    this is the power supply thats not working i checked it out as best i could for any shorts, broken contacts and burned out components (only prob is i dont now the difference between a damaged resistor or a working one same for the capacitors

    if u can help me out even a little or point me in the right direction it will be so helpfull
     
  5. agent420

    agent420 What's a Dremel?

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    That might be a tough one. Especially since it looks like the ccfl inverter is on the power board; substituting another power supply will still leave you with a dark screen. You are probably better off repairing or replacing the power board. Unfortunately, that's kind of a 'hands on' type of thing. To be honest, if you can't diagnose the the problem, replacement is going to be your best bet imo.

    [edit]

    I note there's no sign of toasted components (that I can see, anyway)... resistors usually burn when they go (but they can also crack and open circuit). You can meter across them to check for shorts or opens. Caps are usually ok if they aren't bulging. If I had to take a wild guess, I'd say one of the switching power transistors... Maybe remove them from the board and test them?
     
    Last edited: 6 Jun 2006
  6. BlackMan

    BlackMan Minimodder

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    do you know for sure that its the power supply blown? it might be something else wrong with it. just making sure thats all
     
  7. RichardKB

    RichardKB What's a Dremel?

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    U2 STS7C4F30L is a common failure on this model power supply/Inverter, replace also the capacitor C2 220uF 25V.



    Regards

    Rich
     
    Last edited: 18 Jul 2006
  8. elctroJunky

    elctroJunky What's a Dremel?

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    Most TFT's I know run on 12V... You might try to find a datasheet on your model.

    Anyway, if you can't find the failure on the power board you'll have to improvise.
    The Inverter can be replaced by a standard CCFL Inverter from modding (already did this with a damaged eBay TFT...).
    You might find the voltages required by the TFT by analysing the components on the power board.
     
  9. ConKbot of Doom

    ConKbot of Doom Minimodder

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    I would be careful of doing stuff like this, I was poking around with an old motherboard, and the switching transistors for the step-down converter for the processor were 30v rated, and I would guess that the processor is powered off of either the 3.3 or 5v rail.



    If you really wanna start fixing the board, it looks fairly simple, (single sided, luckily) just start making a schematic for it, and looking up part numbers for ICs and transistors, and possibly the transformer too, if you can figure out how the power supply works, then you can start probing it with a volt meter and see whats working and whats not.
     

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