Can anyone see why this IR sensor/board isn't working? (Pics)

Discussion in 'General Electronics Chat' started by PJ_83, Aug 1, 2015.

  1. PJ_83

    Thread Starter New Member

    Aug 1, 2015
    Hi there!
    I'm very new to electronics (today, actually..). Our bathroom tastic has been working intermittently for a while now and finally stopped. I pulled apart the IR sensor and found a broken capacitor. I went out and bought a new capacitor and soldered it in. I expected it to work straight away but it doesn't.

    Pics of board before and after: (First two are before, second two are after)

    I've checked the IR remote by viewing it through my mobile camera and indeed it is emitting an IR signal.

    Can anyone see why this board wouldn't work? Bad soldering? Or is there something else wrong? Any help is greatly appreciated and will save me buying a whole new unit.

  2. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
    This board is not the entirety of the remote control receiver/decoder system, this part just demodulates the IR signal and sends it off to be decoded. The capacitor is probably just for decoupling and the receiver will probably work without it so, although it may have failed, it is not necessarily the cause of the problem.

    You really need to put an oscilloscope on the output to determine it the coded data is present when the remote control is operated; if this is the case then the fault is likely to be at the other end.

    First check there is power on the board. If you don't have an oscilloscope, you could connect an LED in series with a 1K resistor between the +V (I'm assuming the Red wire) and the output (white wire ?) and see if it flashes when the remote control is operated.
    Last edited: Aug 2, 2015
  3. PJ_83

    Thread Starter New Member

    Aug 1, 2015
    Thanks very much for the answer!

    I don't have an oscilloscope - but will try to do what you have suggested with the LED and resistor. Also I'll try to dig into the main board (it's in the roof) and see if I can see anything wrong with the circuitry there too.

    Thanks again. I'll keep you updated.
  4. Brevor

    Active Member

    Apr 9, 2011
    You should clean all the corrosion off the board, grey stuff around the connector pins. You can use a toothbrush and clean water. Let it dry before you test it. Also look closely at the copper traces make sure none of them have been eaten through by the corrosion.