Installing a "intergrated circuit 3 term. voltage regulator... HELP!!

Discussion in 'General Electronics Chat' started by flaxfilly, Oct 2, 2009.

  1. flaxfilly

    Thread Starter New Member

    Oct 2, 2009
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    I have a "Rope It Up" Arcade Game.... It's about rodeo... Any way this crudly built table was made in 1993-1995. Only 5 were made. I have dusted it off, cleaned it up, and all works well other than the "timer display" wont stop when the button is pushed. Tearing into the "box of wires" I see this circuit board which appear to have come "un-glued"... under where it was glued was a small voltage regulator that was bolted to the box. Now the circuit board and the regulator both have 3 male prongs.... well i messed around with it till I blew up the old regulator, bought another from radio shack, (the fella there did not even want to look at my "box of problems", or thinking I was just a silly ole girl I could not be helped) any how.... I now sit here with the parts and wonder, should the 3 prongs be touching each other, was there a female part connecting them, does it just "arc" to make a connection.... Oh, by the way, I dont know what Im talking about really..... there have been many men looking at it, scratching their heads telling me the tech names of these little gadgets. I was told the circuit board 3 prong connection is probably a condenser, all I know is when it's not plugged in, that thing will still spark :eek:..... whew... gettin kinda jumpy here in the sticks, lookin for any help other than driving 4 hours to take it to a pro.... any ideas??
     
  2. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Welcome to AAC.

    A picture is worth... Can you get an in-focus picture of both sides of the board and objects you think might be hooked together?

    John
     
  3. flaxfilly

    Thread Starter New Member

    Oct 2, 2009
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    got one more coming in next post, hope this helps, you can see on the bottom of the box, where there looks like paint missing where they were attached
     
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  4. flaxfilly

    Thread Starter New Member

    Oct 2, 2009
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    last pic, really appreciate any help!
     
  5. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Okay. This picture labels the components.

    [​IMG]

    The thing with the notch on the corner is the voltage regulator. The tubular things are the capacitors. The second picture you post shows where the voltage regulator goes. That is, in the three holes that don't have anything sticking out. The 4 wires are two for AC in (the white ones from the transformer), and two for DC out. Black is almost certainly ground/negative; and red is positive. The voltage regulator (VR) will have a number on it, maybe something like 7805 0r 7812... The last two digits are its voltage.

    Can you read that number?

    It solders into the board. To be absolutely certain which way it goes, we need to see the back side of the board. The side with the printer circuit connections. The view you show is oblique and I cannot tell which trace is which. If you can get a more straight on view, it would help.

    In order to fix this, you will need a soldering iron and a way to remove the old solder from where the voltage regulator fit. Sometimes you can just shake the molten solder off. A better way is to use "solder wick" or "solder braid." Those are braided copper wire. You heat them in the solder you want to remove and they just suck it up. Then you insert the correct VR in the correct orientation, resolder, and it may/should work. Since there are only two ways to insert the VR, you could play roulette with it, but I would not advise doing that. The capacitors are old, they may work or they may not. Sometimes an old capacitor will expand and "explode" letting out steam. It is not a violent explosion, but it will make a big cloud of funny smelling smoke. I would suggest having the device in the garage or someplace where such a mishap will not cause a problem when you first apply power.

    John
     
  6. Wendy

    Moderator

    Mar 24, 2008
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    Yes, the number off the 3 terminal device would be extremely informative. Interesting project Filly.
     
  7. flaxfilly

    Thread Starter New Member

    Oct 2, 2009
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    Ok, I blew the old vc, but got a new one it is a ECG968.... I know which way to solder them tog..... it is in a shop.... will try it, if I blow the capicator, can I get a new one? where? wish me luck!
     
  8. Wendy

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    Mar 24, 2008
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    It may not fit as neatly as the original, but caps are generaly among the easier components to replace.

    Is ECG968 the number on the 3 terminal device?

    **********************************

    OK, it is a 15V regulator, here is the data sheet.
     
  9. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    WRT the capacitors, yes, they are easily replaceable. Among the numbers on the package for each will be a voltage rating and a capacitance, probably in microfarad (symbol: ufd). Just get the same or higher voltage and capacitance (within reason) for each. They are called "aluminum electrolytic capacitors" or just electrolytic capacitors. They will have a banded/marked side that goes to negative. In other words, they must be oriented properly or they most certainly will release the gases I mentioned as they explode.

    If you are in the USA, Radio Shack may have the capacitors. Otherwise, there are many electronic suppliers, but what is best for small purchases will vary with your location? Are you in a large city?

    John
     
  10. Wendy

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    Mar 24, 2008
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    It is compatible with a LM7815. My part here is done. :D
     
  11. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    A three terminal voltage regulator typically has these three functions for the three pins:
    Input
    Ground
    Output


    In a few cases, the three terminals are:

    Input
    Output
    Adjust

    Check the data sheet for the part.
     
  12. flaxfilly

    Thread Starter New Member

    Oct 2, 2009
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    Ok, it fit reall pretty good.... that pic on the spec sheet is it.... got er solder'd on there.... feelin kinda goosy about pluggin it in, but what the heck, only live once.... thanks guys.... Your my hero's..... if I get it up and runnin, I will post a pic of the "dinasor" in action!!
     
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