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switched fan problem

Discussion in 'General Electronics Discussion' started by lilfear1, Jul 30, 2016.

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  1. lilfear1

    lilfear1

    21
    3
    Jul 30, 2016
    I have a 12v .37a pc fan, a on/off switch with 3 pins on the back to solder to...two of which are soldered together (as they were when I removed them from something previously...and a, i think is a Li-ion battery 3.7v 230mah again something i removed from something...I have connected these all together and the switch works. However, when I turn it off the fan does not come back on unless I physically disconnect the battery or have a laps in connection.

    This sounds like a short to me, I am thinking inside the switch but I have no idea. I am getting 3.9v from the battery. When connected to switch/fan works great, then when i shut off the switch and it dont come back on I check voltage at the switch and no matter what side it is on there is no voltage until I do the disconnect...

    Sorry this is so long, it's almost 4am and I think i should have gone to bed a few hours ago rofl. Any ideas as to my problem?
     
  2. Harald Kapp

    Harald Kapp Moderator Moderator

    10,806
    2,437
    Nov 17, 2011
    DOes the fan turn n and off without issue when you remove the switch and connect and disconnect the fan directly to the battery? If so, inspect the switch with an Ohmmeter. Does it work correctly? Do you have another switch at hand to cros check the function?
     
  3. lilfear1

    lilfear1

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    3
    Jul 30, 2016
    I have checked that and yes everything works properly, I get continuity on one side of the switch, and when i switch it the I get no continuity...that is how they work in case someone didn't know...the fan works fine with just the battery attached and correct continuity at the switch but when i attach it all works until I turn off the switch (without disconnecting the battery) but won't come back on unless I disconnect the switch.
     
  4. Harald Kapp

    Harald Kapp Moderator Moderator

    10,806
    2,437
    Nov 17, 2011
    I suggest you get another switch.
     
  5. lilfear1

    lilfear1

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    Jul 30, 2016
    why would the switch be bad?
     
  6. HellasTechn

    HellasTechn

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    Apr 14, 2013
    Overheated with solder iron ?
     
  7. lilfear1

    lilfear1

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    3
    Jul 30, 2016
    but the fan comes on and off when i use the switch...the sound isn't coming from the switch.
     
  8. HellasTechn

    HellasTechn

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    Apr 14, 2013
    Ok try unsoldering the switch contacts, All of them then connect the (+) battery terminal to the middle pin of the switch and one of the two remaining pins to the positive (probably red) of the fan.
    Connect the negative (probably black) from the fan to (-) of the battery and toggle the switch to see if it works
     
  9. lilfear1

    lilfear1

    21
    3
    Jul 30, 2016
    well it is not connected to a battery anywhere. so I am dealing with AC not dc...the power supply I am using switches ac to dc to make everything work...I do have pin 1&2 tied together and 3 separate. With AC it shouldn't matter + or - . The plug of the power supply (sitting on top of the box in the picture) does not even care which way it is plugged in.
     
  10. HellasTechn

    HellasTechn

    1,544
    215
    Apr 14, 2013
    Theese are DC fans, they will not work with AC.
     
  11. lilfear1

    lilfear1

    21
    3
    Jul 30, 2016
    ok I am really confused now. this power supply I am using switches ac to dc there for with the fan being dc it should work just fine and both are also 12V. I am adding picture of the power supply I am using. well crap for some reason no matter what picture I take even changing settings it wont upload but I put one on first post that was bigger...I dont get it...the power supply I am using is called a switching adapter ubee model DSA-12g aus 120120
     
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