24V neon decoration light effects?

Discussion in 'The Projects Forum' started by smilem, Nov 28, 2010.

  1. smilem

    Thread Starter Active Member

    Jul 23, 2008
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    Hi, my Christmas lights controller (china made) went dead, obviously I would like to make them work again. I found some circutis on the net, but they all were LED based.

    Power source is: AC 24V wall adapter.
    Lights are: Neon lights (~19ohm per strand)
    There are 5 wires.
    Each strand pulls about 350mA (total 1.5A)

    Wire 1 is common wire
    Wires 2,3,4,5 make separate parts glow.

    Is there some 24V schematic I could use to make it blink, chase etc.

    Thank you.
     
  2. marshallf3

    Well-Known Member

    Jul 26, 2010
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    I have serious doubts that you've got neon lamps, just regular ones, so common sense applies.

    Can you measure ohmmage on the strings? Is the controller box trying to switch?
     
  3. bertus

    Administrator

    Apr 5, 2008
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  4. smilem

    Thread Starter Active Member

    Jul 23, 2008
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  5. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Do you want some "flaming" in the lights?
    Almost all circuits in electronics are for DC.
    Your powersource is an 24 Volts AC wall adapter.

    Bertus
     
  6. smilem

    Thread Starter Active Member

    Jul 23, 2008
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    Well the adapter is made in Germany. It's not DC but AC 1.5A.

    I checked it by measuring, and it's written: AUSGANG 24V~ AC
    Furthermore the controller board had it's own bridge inside from 4 diodes.
    There were obviously 4 transistors to flash the lights and IC chip that is dead now.

    I can make a photo of the controller if somebody would help me reverse-engineer it to make it blink, flash etc.
     
  7. Wendy

    Moderator

    Mar 24, 2008
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    My guess is the voltage was converted into DC in the controller. From there that IC, which was probably a PIC, could do tricks. The transistors were to handle power.

    I also predict that the wire bundle had more than two wires, To allow for special effects.

    LEDs, 555s, Flashers, and Light Chasers

    Chapters 9 and 10. A microcontroller can do things with much less space.
     
  8. smilem

    Thread Starter Active Member

    Jul 23, 2008
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    So, here is the controller PCB, the hole in the center with 10 track going to it is the place where I desoldered another small PCB with the CHIP that was controlling it. I tried to see what it was but it was coated with black epoxy.
     
  9. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    The "black dot" was a chip on board integrated circuit. To save costs, rather than putting the IC into a package with leads, they simply put the ic onto the board, bring the leads out to the traces, and encapsulate it in epoxy.

    It was most likely a custom logic/uC IC. The driver transistors are still there, so any 4 output sequencer could be used to drive them and turn on the lights. See Bill's blog (link above) for ideas on how.

    If it hasn't been physically damaged, the sequencing board may be fine, and the transistors or power supply failed, would need more info and some measurements when it is assembled to have an idea though.
     
  10. smilem

    Thread Starter Active Member

    Jul 23, 2008
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    I have updated the PCB picture. I have marked PINS and tried to track them.
    Here is the updated PCB.

    I looked at Bill's blog and could not find 4 output sequencer, do you mean this:

    Chapter 9: Light Chasers

    I could connect the 4 outputs of IC 4022 to transistors (Pins 3,4,5,6) to drive the lamps right?
    http://pdf1.alldatasheet.com/datasheet-pdf/view/82916/UTC/PCR406.html

    What do I do with other pins how wire them?
     
    Last edited: Dec 2, 2010
  11. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    SCRs do not work like transistors do, they stay on once turned on.

    The best way to do this would essentially be discarding that board, and starting over with a single mode sequencer. You could use one of Bill's Circuits for that, if there are more than 4 outputs, we can cut it down to 4.

    I am thinking of setting it up as a "chaser", where each LED would light in turn, 1-2-3-4, so the whole string would look like it is moving.

    Do you have a DMM? We'll need to voltage drop of the diodes in each of the 4 strings, I am guessing they are in parallel to support that many LEDs. Are all of the lights in each string the same color?

    The hardest part of making an LED chaser is usually getting the LEDs onto the wire in the right order. You have that part done.
     
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