1. SlegBE

    OP SlegBE Member
    Newcomer

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    Hello,

    I bought a Switch to be repaired.
    Nothing on the screen after pushing power button and after first check I changed PI3USB.

    Switch can now charging and power on. It works perfectly... in handheld mode and no TV signal on docking mode
    I read I'm not alone with this recurrent problem.

    I checked :
    filters => continuity OK
    capacitors nearby PI3USB and M92T36 => no shorts

    I decided to check with battery and USB cable plugged and discovered that the 4 capacitors below PI3USB have no power. (0.09v instead of around 3.3v)

    So, can someone tell me if capacitors are bad or is it PI3USB or another component who supply voltage to these capacitors ?

    Thanks for help ;-)


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  2. SlegBE

    OP SlegBE Member
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    According to the datasheet these at least 4 pins (32,29,26,23) from PI3USB are VDD so I understand that it is not the chip who provide the power but received it from the board.

    I also read on previous post:
    *********************************
    If no image on HDMI docking - Check 3v is getting to the PI3USB.Ok but where to check if it hasn't voltage ?
    I would also check if the dock LED go green and the TV attempts to find a signal. Yes it has.
    Check around the passives around PI3USB. In particular the ferrite filters. These are quote weak!! check impedance & continuity is uniform with all of them. Correct

    *******************************

    I 've just changing M92T36 even it has no shorts, but no improvement. Still no 3v on these 4 caps.
    I think it will be possible to have a faulty component between output of M92T36 and VDD of PI3USB.
    Do you have an idea ?



    Capture3.PNG
     
  3. SlegBE

    OP SlegBE Member
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    Hello,

    Nobody for an advice ? A little help would be appreciated...
     
  4. Pintglass

    Pintglass GBAtemp Regular
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    Have you got 3v3 on the large cap above PI3USB?
     
  5. SlegBE

    OP SlegBE Member
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    Damned just wanted to measure the caps value. I connected battery and put original charger into USB port and had a fire into PI3USB :blink:
     
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