4 Channel LED colour organ not working

Discussion in 'The Projects Forum' started by Max12345, Oct 6, 2013.

  1. Max12345

    Thread Starter Member

    Aug 27, 2013
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    Greetings
    I've built a 4 channel LED colour organ using a circuit by Ledartist.
    All the LEDs come on and stay on without audio input.
    Assuming that there are no faults on my veroboard, what could possibly be the cause/s? I've checked and rechecked the circuit and the layout and cleaned the flux.
    I just need some pointers on where to look.
    http://www.instructables.com/id/Color-Organ-Triple-Deluxe-II/





     
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    What is the supply voltage?
    What are the voltages on the bases of Q3, both Q5s, Q7?
     
  3. tubeguy

    Well-Known Member

    Nov 3, 2012
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    +1 If you were using a 12VDC supply you should see about 0.43VDC on those transistor bases; the LED's would be off with no audio signal.
    Wild guess > are the 270K resistors the correct value (270,000 ohms)?
     
  4. Max12345

    Thread Starter Member

    Aug 27, 2013
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    Hi guys
    Alec_t, the supply is 12V.
    Tubeguy, the 270K resistors are correct as per Ledartist's circuit.
    I have uploaded ALL the base voltages on the new "Original and changes 2" schematic for your perusal.
    Thanks so much
     
  5. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Those voltages are seriously not what they should be. Double-check that you have the pin-outs of the transistors correct.
     
  6. MrChips

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    Oct 2, 2009
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    I agree. There is something dramatically wrong with your setup.
    Post clear well focused photos of both sides of your circuit board.
     
  7. Alec_t

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    Sep 17, 2013
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    Check also that the bottom ends of R9,R14,R19 are properly grounded.
     
  8. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    When my prototypes don't work, my first assumption is that there IS something wrong with my wiring. Using a marked up schematic increases the likeliehood that something is wired wrong. The easiest thing to double check is the pin out on the transistors; viewed from the flat front, the leads are l to r, c, b, e.

    Did you breadboard the circuit before you put it on veroboard?
     
    Last edited: Oct 7, 2013
  9. MrChips

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    Oct 2, 2009
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    Not for 2N2222A it ain't.
     
  10. tracecom

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    Apr 16, 2010
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    Note to self: don't go by memory. :)

    (Original post corrected.)
     
  11. Max12345

    Thread Starter Member

    Aug 27, 2013
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    Gents, you've found the problem (sheepish grin).
    I used the P2N2222A pinout configuration for the KSP2222A and they are not the same! My transistors are connected wrong way round.
    The store at which I purchased the transistors has a datasheet of their transistors and when I clicked on the sheet for the KSP222A, the sheet of the P2N2222A came up and I assumed that they were identical. Assumptions...

    http://www.mantech.co.za/Stock.aspx?Query=ksp2222aand


    Tracecom is correct in his layout of the P2N2222A, although I think that the 2N2222A is a can. That is the way I have it on my vero.



    So are they all shot now? Or should I still bother to check them before buying others?






     
  12. Max12345

    Thread Starter Member

    Aug 27, 2013
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    I didn't, my breadboard is too small...(another sheepish grin)
     
  13. Alec_t

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    Sep 17, 2013
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    Probably not. Re-connect them right way round and give 'em a try.
     
  14. MrChips

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    Oct 2, 2009
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    Well, Alec_t had said it first. I looked at your photo and figured you had connected it correctly.
    I reversed the pinouts in a simulator and did not arrive at your values. So I assumed that you had another problem somewhere.
     
  15. Max12345

    Thread Starter Member

    Aug 27, 2013
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    So he did, MrChips, so he did. Thanks Alec_t.
    I'll whip 'em out and replace them and see...
    Thanks again
     
  16. tracecom

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    Apr 16, 2010
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    Well, I was confused as well. I keep and use the PN2222A, which has a l to r pinout of e, b, c. My mistake was in not realizing that the 2N2222 is a can with a different pinout; I thought they were just two different numbers for the same thing. When I looked at the photo, that confirmed my erroneous belief, all of which is the reason I posted wrong info about the 2N2222 and had to correct it. Thanks to MrChips. :)

    I am sorry for any confusion I caused, but I learned something I won't soon forget.
     
  17. Max12345

    Thread Starter Member

    Aug 27, 2013
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    All the transistors worked, except 1, which also worked, but only dimly switched on the LED in my transistor tester, so I replaced that one.
    Circuit works now, thanks.
    However, now I have to work on the filters. A link to a sound card generator given to me by bertus, shows that there is too much overlap between the bands.

    http://www.twopaths.com/Software/index.htm
     
  18. Alec_t

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    Sep 17, 2013
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    Glad you got the main problem sorted out. Let us know how you get on with the filters.
     
    Max12345 likes this.
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