Help with Sony VAIO P FFC connector

Discussion in 'General Electronics Chat' started by viiv, Aug 28, 2011.

  1. viiv

    Thread Starter New Member

    Aug 28, 2011
    3
    0
    Hey everyone. I should point out I only have the most basic of electronics knowledge before I proceed here. Anyways I own a VAIO P series laptop which has been great except for one problem.

    The P laptop employs as pointer stick in the keyboard for the mouse instead of a touchpad. There is a FFC membrane cable the runs from the pointer stick underneath the keyboard to a ZIF connector on the board. The problem with this computer is if pressure is applied to the casing of the keyboeard where the ribbon cable runs underneath, it causes the mouse cursor to move erraticly. Im not exactly sure why though.

    The good news is there is a fix by Sony as outlined by their service manual here:

    http://computercowboy.com/Downloads/VPC-P11.pdf

    The fix is located on the last page of the service manual on page 21 of the document. The fix is to tape the FFC coming from the pointing stick down with a tape harness near the ZIF connector on the board as indicated by the diagram on the bottom of page 21. Anyways wanting to do this myself I went to the local parts distributor and brought a few pieces of this official 'tape harness' (its just tiny pieces of tape) for a few bucks and set about to open the laptop and apply the tape.

    Now the problem is after I put the computer back together the problem is WORSE. Its even MORE sensitive to pressure now. Before you'd have to press fairly hard on the casing to to get the mouse to move. Now even pressing the left ALT button makes the mouse cursor move making the computer unusable.

    I'm wondering what did I do wrong. Interestingly enough on page 19 and 20 of that service manual there is another bullutin about that exact same FFC cable warning you to be careful when removing it because if you do not unlock the connector you'll strip the graphite on the male FFC connector.

    The only thing I can think of is I when I taped the FFC down, it cable was pretty taught in the 10mm or so between the tape I laid down and the connector. Should I have pushed 'slack' into the cable between the tape and the connector, forcing a 'ripple' or something in the cable? I'm not sure if I did a good or poor job of 'reinforcing' that fragile connector.

    I still dont understand what exactly is the cause was for the mouse pointer to move. Is it stray electrical signals getting into the cable? Is the cable 'floating' or being loose causing these unwanted impusles going into the board? I don't exactly understand anyways how taping down this FFC ribbon cable is supposed to stop that because...it made the problem even worse now.
     
    Last edited: Aug 28, 2011
  2. iONic

    AAC Fanatic!

    Nov 16, 2007
    1,420
    68
    From where I stand, you have two possibilities.

    1) Buy a replacement keyboard and risk rubbing the graphite off the connector while inserting it into the slot.

    2) Buy a cordless optical mouse and disable the keyboard mouse thingy.

    Note: I actually repaired a similar cable using some liquid graphite compound by painting the connector lines back on.
    I think it was called solder-less glue.
     
    Last edited: Aug 28, 2011
  3. viiv

    Thread Starter New Member

    Aug 28, 2011
    3
    0
    But I actually never removed the FFC from the connector. All I tried doing was taping down the FFC cause from what I understand when it moves it causes the pointer to move but it made the problem WORSE.
     
  4. iONic

    AAC Fanatic!

    Nov 16, 2007
    1,420
    68
    Can you undo what you did without more harm?
     
  5. viiv

    Thread Starter New Member

    Aug 28, 2011
    3
    0
    Yes, but before I do that I want some experts opinion. Do I just completly ditch the tape? Or do I put a new piece of tape and push some 'slack' between the tape and the connector? Is that called properly bracking a connector cause right now its taught? I didn't pull the FFC out of its connector at all, I just taped it down as you see in the PDF so it doesnt move. But maybe cause its taught, it makes it more sensitive?


    But really what I am asking is from a pure scientific level, what would cause the computer to be picking up stray movements of the pointer stick that dont exist through the FFC? If you 'flex' an FFC does that cause random minor electrical spikes?
     
  6. iONic

    AAC Fanatic!

    Nov 16, 2007
    1,420
    68
    Giving it some slack might help. Try getting on a SONY forum and ask about it.
    You'll get the most experience with respect to the problem.


    As far as a purely technical explanation I wouldn't be the one to ask.
     
Loading...