Think I fried something. More noob electronic project help.

Discussion in 'The Projects Forum' started by Todd W. Roat, Nov 6, 2015.

  1. Todd W. Roat

    Thread Starter New Member

    Jun 7, 2015
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    Pretty new to wiring and electronics, be gentle. Been buying some odd man cave electronics and wiring them. Doing pretty good until this last one where I took a chance and think I screwed something up. Wondering if its salvageable.

    Have a school bus backup light. Foolishly (but heck, you gotta learn right ;) hooked a standard ground plug to it (white black ground) GUESSING what to connect to what. I guessed wrong.

    There was a hiss, a whoosh of air, and a burned smell from what I believe is some kind of ballast (see bottom picture, green thing on left). It only has a Red and a Yellow coming from it. See pix below.

    Questions are:
    1. Possible I didn't kill it?
    2. How can I get power to the Red and Yellow power wires?
    [​IMG]

    [​IMG]

    [​IMG]
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    It sounds like you hooked up a low voltage system to 120vac?
    No wonder, if so!!
    Max.
     
  3. Todd W. Roat

    Thread Starter New Member

    Jun 7, 2015
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    Got it. Likely the case. The assumption then is a school bus would be using low voltage to feed this thing? Are there any alterations I can make to get a standard 110 house plug to light this baby up - presumably bypassing the low voltage components? Thanks for the reply.
     
  4. Todd W. Roat

    Thread Starter New Member

    Jun 7, 2015
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  5. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    It looks like there is a diode on the far right side and a TO-3 transistor. Can you draw a schematic of the circuit starting on the left of your drawing with the yellow and red wires and work your way across. Assume that the wires attached to the metal frame are ground (0v).

    Also use a mirror to read the part number off of the transistor and Post it here.
     
  6. Todd W. Roat

    Thread Starter New Member

    Jun 7, 2015
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    I dont know the correct symbols to make a diagram. It might be better to show you closeup shots of the wiring - seems like that would be better than any incorrect diagram I could draw.

    Diode: One side said F7WL (the F may be a P), other side 5XM 10

    Transitor reads 176

    [​IMG]
    [​IMG]
    [​IMG]

    While I suspect I toasted the flasher, all I really want it to do it light up - attach a standard lamp plug to it with a switch.

    Thanks!
     
  7. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    Either replace the bulbs with a mains rated fluorescent/ CFL/ LED lamp(s) or, and this is the safest option for you, run the existing bulbs from an external low voltage DC power-supply. What is the voltage and power rating of each bulb?
     
  8. Todd W. Roat

    Thread Starter New Member

    Jun 7, 2015
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  9. crutschow

    Expert

    Mar 14, 2008
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    I trust by now you realize that there's a world of difference between 12Vdc and 120Vac? :rolleyes:
     
  10. Todd W. Roat

    Thread Starter New Member

    Jun 7, 2015
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    Yes sir. NOW I do ;^) Direct vs alternating. As I mentioned, half the fun is learning something new. So those links are for alternating but when I refer to plugging it into wall socket that would be DC, correct ;^)
     
  11. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    Seriously! Don't you think that 12V vs 120V is somewhat more relevant? Your misunderstanding could easily have been fatal and that would not have been fun. Your light might have survived 12VAC and humans certainly will.

    Does post#9 suggest that the wall socket supplies DC? (Hint: the wall socket is the 120V option)
     
    Last edited: Nov 7, 2015
  12. crutschow

    Expert

    Mar 14, 2008
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    Okay, I believe you need a few basics. :rolleyes:

    AC is alternating current, such as comes from the wall socket.
    The voltage alternates between plus and minus value at either 50Hz or 60Hz depending upon where you live.

    DC is direct current, such as comes from a battery.
    It does not change its voltage value with time (a least for the short term).

    AC cannot generally be substituted for DC (and vice-versa) except for certain simple devices (such as an incandescent light bulb).

    Voltage is the pressure behind the current.
    The wall socket is 120V or 240V (again depending upon where you live).
    12V (up to about 50V) is not dangerous and generally can't be felt when you touch a live wire with that voltage.
    120V/240V is dangerous and can kill you or, at a minimum, give you a nasty shock (which you usually don't want to experience more than once).

    You don't want to mess directly with the wall voltage unless you really know what you are doing.
    That's why transformers or wall-worts are used to convert the 120/240Vac wall voltage to a safe and isolated lower voltage DC or AC.

    Trust this info will help keep you from being a Darwin Award nominee. ;)
     
    Sinus23 likes this.
  13. KJ6EAD

    Senior Member

    Apr 30, 2011
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    While the original trade number 1195 lamps had a total light output of 2500 lumens, two were probably on for general illumination while the other two flashed alternately (wig-wag) at 50% duty cycle each and since your intent is a room decoration, not a signalling device, I suggest the following.

    Remove the lamps, lamp holders, flasher circuit, transistor, all wires and all brackets. Clean, prep and spray paint the interior of the backbox white. Purchase and install a flat panel LED as large as can fit in the backbox (something similar to the ones in the link below). Re-assemble the face plate to the backbox. Hang the completed backlit marquee light in it's intended location. Plug in the cord.

    https://www.superbrightleds.com/cat/led-panel-light/filter/Dimensions,6in_x_6in,149,7847:
     
    Last edited: Nov 8, 2015
    wayneh likes this.
  14. Todd W. Roat

    Thread Starter New Member

    Jun 7, 2015
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    As much as I would like to try and salvage the interior (and just get some lamp plug wall power to the bulbs) this might be the easiest solution.

    I have an older Emergency Exit light as well. Basically same concept minus a flasher. It has a lamp plug feedeing wall 110 to it and it lights up. Seems like there must be some way to do the same for this BackUp light. BYPASSING all the interior original content (to preserve its historic components) but deliver wall 110 power just to the bulbs.

    Crap, there I go again, making it too complicated.
     
  15. wayneh

    Expert

    Sep 9, 2010
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    You could use the same sort of guts that your exit light uses, or go with a more elegant solution using LEDs. The latter will waste less energy and you'll probably learn more tricks that you can apply to future projects.
     
  16. Todd W. Roat

    Thread Starter New Member

    Jun 7, 2015
    21
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    Gut replacement is the best option I suppose. So is there a favorite web site (other than Radio shack) to order from that you guys use for electronics?
     
  17. wayneh

    Expert

    Sep 9, 2010
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    I use Mouser, DigiKey and Newark. But everything you need for this project might be at the hardware store.
     
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