cross talk elimination

Discussion in 'General Electronics Chat' started by electronis whiz, Jul 27, 2012.

  1. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
    519
    27
    i am working on another gateway LCD i was given. indentical model to my current one i am useing that had a bad cap in the PSU. the symtopm is linse faint (but normaly visable) lines scroll across the screen apears to be from left botom to top right (as viewed from the display) normaly. but may change left to right. I opened it checked all the caps for bulges and they all loked ok. then i went to my crostalk theory. i disconected the signal cable from the logic board to the LCD removed the metalic tape that sheilded it, then taped all the wires flat and replaced the original metalic tape. the wires are twisted into pairs with a few single wires also. after i layed them flat it improved but not completly. i'm now thinking of using tin foil or the original tape and wraping the pairs individualy. then posibley conecting them together then to the chasis that is grounded. i would think this would eleminate posible crosstalk but not sure. will my idea work?
     
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  2. lokeycmos

    Active Member

    Apr 3, 2009
    432
    7
    its hard to say forsure. give it a go and tell us the results
     
  3. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
    519
    27
    I tryed it. used aluminum foil about 3 pairs per. sheet then taped them together. also did the same for a few single wires. it improved quite a bit instead of lines scroling now it just sort of looks like a somewhat poor refresh rate. i may check that also and see. same symptom came with 2 VGA cables, but i have a havy duty probley shelded one i may try see what happens. my foil wraping does ran over a metal PCB cover so it should be grounded, may see if i can conect it useing wire to be sure and make sure resistance is minimal. seems kind of odd that crostalk seems to be the isue. the person i got it from said it just started one day. but it was from a coledge so i'ts posible it had some abuse. i almost thpought capacitor, but near as i can tell there all ok.
     
  4. lokeycmos

    Active Member

    Apr 3, 2009
    432
    7
    i just thought that if you think the cable is causing issues, you may be able to locate a replacement cable for a few bucks on ebay. not sure if this is helpful, just an idea.
     
  5. chrissyp

    Active Member

    Aug 25, 2008
    82
    10
    just a thought, if the single wires in the wrapped wires are power and the twisted pairs are signal it may work to wrap them separate bundles to help eliminate the problem
     
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