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Bridging a laptop volume wheel.

Discussion in 'Troubleshooting and Repair' started by wildscot, Jun 18, 2011.

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  1. wildscot

    wildscot

    4
    0
    Jun 18, 2011
    Hi,

    I have an old Toshiba Satellite A10 that it's become a bit of a mission to keep alive.

    It has a manual volume wheel which has been damaged and I'm pretty sure I can bypass it by soldering across the contacts.

    I'm a total novice and would like a little advice from someone more experienced before I start diving in.

    The damaged wheel had a disk on the underside that made contact across 5 connectors, these are marked where they join the board as 1 to 5.

    Instinct tells me to bridge 1 and 5 to 'fix' the volume at the maximum but this is just a guess. I'm also unsure whether to just join these two or all of them, 1, 2, 3, 4, 5.

    It's proving impossible to get a photo of the part so I've drawn it and tried to scan the contact from the wheel.

    Any advice would be much appreciated.
     

    Attached Files:

  2. Resqueline

    Resqueline

    2,848
    2
    Jul 31, 2009
    It not quite possible to tell which contact goes to which ring from the drawing, but I'm sure you can identify which ring they make contact with on the disk.
    I've identified the function of each ring (though I can't tell left from right) and you need to bridge Left In to Left Out, and Right In to Right Out. (Two separate bridges.)
     

    Attached Files:

  3. wildscot

    wildscot

    4
    0
    Jun 18, 2011
    That's brilliant, thanks so much.

    Just as well I didn't jump in with both feet and start soldering at random.

    You're right, I can work out which contact meets, I've mocked it up on a really distorted picture just in case it's useful to anyone else. I'll post back if it works out.

    Thanks again.
     

    Attached Files:

  4. wildscot

    wildscot

    4
    0
    Jun 18, 2011
    Still no luck I'm afraid. I know the computer is capable of sound as it worked before I changed the motherboard and I have been able to get faint sound since if I've managed to get the wheel in just the right position.

    I've soldered wires bridging the contacts as mentioned above, excuse my total ignorance here but do I have to link the ground wire to something to complete the circuit and if so what/where?

    I've attached a picture of my shoddy solder job if that helps.

    I've attached 1 and 4 (right input and right output) at the solder pads and 2 and 3 (left input and left output) at the connectors due to the tight space. Although the soldering is terrible I'm pretty sure that there's no connection where there shouldn't be.

    I'd love to keep this old machine running so any help is appreciated.
     

    Attached Files:

  5. Resqueline

    Resqueline

    2,848
    2
    Jul 31, 2009
    Looks ok to me. I wouldn't think anything would need to be grounded, but the original pot does load the audio with some 2k-20k ohms. Do you have a DMM?
    Try to touch a resistor (if you have) in the 1k-22k range from the links and to ground.
    There are many other reasons for the audio to fail in a laptop. I don't quite know what to suggest - what to try.
     
  6. wildscot

    wildscot

    4
    0
    Jun 18, 2011
    I don't have a DMM unfortunately.

    At this point I think I should maybe admit defeat before I 'fix' it to death. It would have been more satisfying to effect a repair but I think a £1.50 USB sound dongle from eBay might be the way to go.

    Thanks very much for your help.
     
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