How to fix this circuit board of submarine toy?

Discussion in 'General Electronics Chat' started by quique123, May 15, 2015.

  1. quique123

    Thread Starter Member

    May 15, 2015
    I have a submarine toy of my kid which I'm trying to fix. I believe it got wet.

    It's a simple circuit with a flat 1.5v battery, a speaker and the small board with a switch.

    How can I troubleshoot this?


  2. ScottWang


    Aug 23, 2012
    Your upload file is to big, so I cut it to two files and compressed them to smaller files.
    1. What is the front look?
    2. How does it works?
    3. What is the problem?
    4. Please attach another photo for component side.
  3. quique123

    Thread Starter Member

    May 15, 2015
    Thanks. And sorry but I was posting from my iPhone and I forgot I was uploading the full res pic.

    It's a submarine that has a button, some leds and a speaker (the white cables).

    When you press the button it plays sounds and lights up the leds. I'm not sure how it randomizes the tracks it plays (cause I don't see an IC anywhere) but there are about 3 different tracks it plays.

    The problem is it doesn't play anything anymore. I press the button but nothing happens, not even a chirp from the speaker.

    I put a multimeter leads on the white speaker terminals and pressed the button but no current flows in.
  4. BR-549

    Well-Known Member

    Sep 22, 2013
    I believe the chip is under the black dome.
    I would remove battery, cover unit in rice and seal in bag for a couple of days.
    Fire it up with new battery.
  5. Dodgydave

    Distinguished Member

    Jun 22, 2012
    get an hair dryer and warm dry the pcb for ten mins, then put the battery on it and try it, if it doesn't work bin it.
  6. GentleRV

    New Member

    Dec 18, 2010
    DON"T heat it up with a hair dryer, It becomes to hot and the black plastic cover (in where the chip is) will get loose and the humidity will do the rest.
    The advice for the rice bag will work and also just let it dry for a week or so will do the good thing too
  7. supremekizzle

    New Member

    May 16, 2015
    +3 on the rice. I have had that work for me on far more complex items (cellphone+toilet bowl :) ) I'm sorry, but it's a little funny that what ruined a toy it getting wet. ;)
  8. quique123

    Thread Starter Member

    May 15, 2015
    Yes, I see the irony. Im not sure why a toy submarine has electronics in it that aren't protected from water.

    My first instinct when my kid got it was to take it into the pool but I figure I shouldn't because of the electronics. But one day it got left outside and it rained.
  9. studiot

    AAC Fanatic!

    Nov 9, 2007
    Yes even if it looks surface dry, there may be moisture in the interstices of the electronics.

    Dry it thoroughly, I usually leave for a few days to a week in free air after scrubbing boards in a washtub.
  10. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    I'd start by checking the battery is ok. Do you have a multimeter?