Zenbook UX31A DC Jack repair problem

Our Zenbook was dropped from less than a foot a month ago breaking the non-official charger's jack plug and cracking the jack socket inside. The laptop continued to work perfectly, until the battery died so this is only a power issue.

I have just replaced the jack socket, however when doing so I think I have damaged the circuit which determines whether the plug is inserted - on the socket are 6 feet, 2x3. The middle 2 are not connected to the other ground pins and presumably are used as part of the charging circuit. Just like the plug sensing of a headphone out on a modern computer I presume.

On one side the pcb has been slightly damaged and now I don't believe the circuit is 'made' when the plug is inserted, even though +ve &-ve DC is connecting fine. see photo:


Does anyone have knowledge of laptop motherboards in this regard, am I right that this failure to make the circuit might be what is causing the laptop to not POST?

If so, then I need to repair this portion of the motherboard - finding a contact somewhere else on the board which is directly connected to the middle missing pin.

Any advice is appreciated, we can't afford to replace the laptop.
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  1. Hi, it's difficult to see the traces on the board, could you take another picture with more light.
  2. jarotech said:
    Hi, it's difficult to see the traces on the board, could you take another picture with more light.

    I'm sorry for the very slow reply, I was away from home for work reasons. I've taken a better photograph.


    You can see the centre-bottom pad is missing and I've soldered a wire to where the trace ended. I've tested this with a multimeter and this now shows conductivity between the centre-top and centre-bottom pads.

    I have also confirmed that DC is getting to the board by scratching away a tiny portion of solder resist and measuring 19V.

    At the connector for the battery I only see 1.8V, which is surprising as I'd expect higher there. The battery is a 7.4V Li-polymer battery.

    I am still seeing the exact same issue however: the laptop's charging indicator (led going orange) does not show, it instead stays green (battery fully charged).

    I have removed the main battery, and also the CMOS one hoping that this would resurrect the laptop but to no avail.

    I've read that there was an issue with some UX31a's coming out of standby and that by holding down the power button for > 30 seconds this would sometimes clear the issue as it presumably cleared CMOS. I've tried this of course and no improvement. I'm also sceptical that this issue should show up at the exact same time as replacing a broken DC socket.

    Any suggestions appreciated. It's impossible to find a replacement motherboard for this otherwise I'd probably just bit the bullet and buy one. I will have no luck on a warranty repair as I've done the jack repair myself, and had bought this second hand.
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