Tactile buttons

Discussion in 'General Electronics Chat' started by Ewans, Aug 25, 2017.

  1. Ewans

    Thread Starter New Member

    Aug 25, 2017
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    Hi hoping for some help. I have a pair of the wife's straighteners. There are 3 smd tact buttons, 1 for power (which works) and another 2 to increase or decrease temperature. These 2 don't work. I tried continuity while depressing and they seem ok. Is there another test I should try on them? Everything else on the pcb appears to be fine.

    Thank you
     
  2. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    Check the heater for open circuit, also there will be a Thermistor and probably a microcontroller.
     
  3. Ewans

    Thread Starter New Member

    Aug 25, 2017
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    Thanks for the reply. I tested the thermistor off the board and reads around 200ohm. Heaters are 164ohm each.
     
  4. Dodgydave

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    Jun 22, 2012
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    Do the up/dn buttons make continuity to the microcontroller pins?
     
  5. Ewans

    Thread Starter New Member

    Aug 25, 2017
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    Hi
    Hi yes there is continuity to the pins.
     
  6. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    So if its powering on, and not heating up, as you have checked the heater,,it must be the microcontroller or triac....
     
  7. Ewans

    Thread Starter New Member

    Aug 25, 2017
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    Yes I think it's the pic. Initial switch on heats up to a preset 150 deg but pressing the + or - buttons nothing happens they just stay at 150. Thanks for your input. Replacing the pic probably isn't an option as I don't think they are commercially available.
     
  8. Dodgydave

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    Jun 22, 2012
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  9. Ewans

    Thread Starter New Member

    Aug 25, 2017
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    Dodgydave likes this.
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