Can this circuit board be repaired? Pics included.

Discussion in 'The Projects Forum' started by newtocicuits, Mar 19, 2016.

  1. newtocicuits

    Thread Starter New Member

    Mar 19, 2016
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    I have a ceramic decoration that is lit with a small 6 watt lamp inside and a few very small bulbs on the outside of the building and the very small bulbs on the circuit board that is pictured, all are powered via a single AC/DC plug 3VDC 800ma output. The inside bulb and the outside bulbs all work.

    I have a Etekcity MU600 Digital Multimeter. From what I have researched and could understand (I have absolutely no idea how these things work, it is honestly very hard to understand for me) I used the settings on the A= side and it showed various reading on the soldered parts of the circuit board. So would the bulbs be the problem? Or do certain numbered readings on the multimeter indicate a problem?

    Is there a similar replacement board that I could use? I have a soldering iron (which I have never used). I contacted the company that made the item but it was a limited edition from 2001 and they do not carry any parts or have info on the board used. I know the bulbs on the board dimmed at random somewhat, because they were used to illuminate a campfire.

    Any help is appreciated.

    Images of the board.

    http://imgur.com/a/yUAWi
     
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    The LEDs on that board are all wired in parallel, so if none of them light then they are not receiving power from the controller hidden under that black blob. So, either the controller is dead, or it is not getting power from the 3V supply.
     
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  3. newtocicuits

    Thread Starter New Member

    Mar 19, 2016
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    Can the controller be replaced? Is there a similar type board that I could solder the two power wires too? I tried another 3V supply and the circuit board still does not light. Is this fixable?

    What settings on the multimeter should I use? I was using the A= and noticed 20m and 200m the other lights flickered, I did not try the 10A. This is the one I have http://www.amazon.com/Etekcity-Digi...8&qid=1458433519&sr=8-2&keywords=ETEKCITY+600

    The numbers on the meter just fluctuate and stay on 0.00 most of the time. The numbers go negative and even go to the left side of the screen.
     
  4. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    I sincerely doubt you'd be able to get a replacement controller or board :(.
    It depends what you are trying to measure. I would expect the central bunch of LEDs to draw about 20mA each, so potentially they could draw a total of ~180mA. The 200mA range would be best for a current measurement, but LEDs are usually their own indicators! The 20V range would cover your voltage measurements.
     
  5. ian field

    Distinguished Member

    Oct 27, 2012
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    If all the LEDs are in parallel; one going short circuit would put them all out.
     
  6. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    There are three circuits, 4 LEDs, 4 LEDs, and the center LED. Two of the circuits have 4 LEDs hard-wired in direct parallel. This is a very poor circuit design technique *unless* the LEDs have current limiting built-in. What does this thing do? That is, how/when/why do the three LED groups come on? Also, what are the LED colors and how bright are they?

    As for repairing the board, probably not. The technique is called chip-on-board. Under the black blob is a bare integrated circuit chip. There are unpotting chemistries to remove the blob, but then what? It almost certainly is a custom chip, or a custom programmed standard part like PIC. Either way, component level repair is...difficult. Your only hope is that it is a bad LED, but with three separate circuits a single LED failure probably would not take down the whole board unless it caused damage to the controller.

    ak
     
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  7. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Good point. I've never known one fail short-circuit, though.
    I missed that. Your eyes must be better than mine ;).
     
  8. newtocicuits

    Thread Starter New Member

    Mar 19, 2016
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    I thought the bulbs were red, because there is a reddish glow from the firepit, but now I think the bulbs are just clear and the red glow comes from the color/material on the firepit, as it has a redness even without the light. There is a glowing effect when it was working, so the bulbs definately have some type of order in how they operate/light up.

    Here is what the item is.
    http://imgur.com/a/OAvaC

    The board is under the firepit. You can see the other bulbs, lit and working.

    I ordered a separate "firepit" made by the same company. This item http://i.imgur.com/h60DP1s.jpg I will take the board out of that one. Hopefully it is just as easy as removing the two power wires and soldering them to the replacement that I remove from the new item.
     
  9. KJ6EAD

    Senior Member

    Apr 30, 2011
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    That replacement may very well be an identical or nearly identical board. If so and the power supply works your problem is solved.

    Another option would be to build a replacement on a piece of prototyping board. You would need some form of current regulation on the board but could use candle flicker LEDs for the effect.

    http://shop.evilmadscientist.com/productsmenu/189
     
  10. newtocicuits

    Thread Starter New Member

    Mar 19, 2016
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    Thanks. I received the replacement and will try to resolder it. Do I just use the normal desoldering methods with this type of board? I have a solder and desoldering wick. Keep in mind I have actually never used them before. I will find some old piece of electronics and use the board to test out. But any help on doing this would be appreciated.

    Because I'm desoldering wire from a board is there anything I should not do?

    Here is the new board (less LEDs, but is still bright enough)

    Images of new board
    http://imgur.com/a/FCl36
     
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