9742 teardown?

Discussion in 'Coby Generation 3 Technical' started by subtotal, Aug 17, 2012.

  1. subtotal

    subtotal Member

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    Hi All

    My 9742 has developed a problem with the speaker, I suspect it's due to a loose internal connection and returning it to Coby isn't really an option due to my location.

    Has anyone seen a teardown for this tablet? Or a guide to cracking it open so I can attempt a repair?

    I'm not really worried about warranty, I just want the speaker working.
     
  2. Traveller

    Traveller Super Moderator Staff Member

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    It's easy to disassemble. Four screws hidden beneath rubber inserts on the back, then pry the unit apart with something thin and flat at the seam and you're in.

    Had to open my roommate's 9742 after the cat knocked it to the floor.
     
    Last edited: Aug 18, 2012
  3. subtotal

    subtotal Member

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    Thanks, just figured that out myself.

    For future reference, if anyone else finds themselves with intermittent crackling / lack of sound from the speakers on this model, you can fix this by rerouting the wires for one speaker so that they don't run next to each other the entire run.
    I suspect that the issue I was experiencing was due to crosstalk between the speaker wires.
     
  4. Traveller

    Traveller Super Moderator Staff Member

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    I'm glad you figured it out, and I'm also glad that your problem was easy to fix. My roommate's problem was a bit more time consuming. When her tablet fell the plastic shell making up the power jack broke in two pieces inside the case and the metal legs on the left and right sides of the back half of the jack literally popped intact off the solder pads.

    As you probably noticed when you opened your unit, the power jack actually has five solder points. The front two are used for a metal strap to hold the jack to the board. The three in the back are for positive, negative, and ground. The strap in the front and the legs in the back have a "foot" which sits on the solder pads on the motherboard. The feet were exposed on the top, meaning not enough solder was used in the wave soldering process to properly hold the jack to the board. A proper soldering job would have the top of the foot covered by solder.

    I may get ridiculed by some people because I haven't enough experience in making changes to Android files, but I do know my way around a soldering iron. I used superglue to glue the plastic shell of the jack back together then proceeded to properly solder the jack to the board, ensuring that the top of each foot was covered by solder. After that, I took two small strips of Gorilla Tape and covered the plastic part of the jack with them.

    I put the tablet back together, tested it and it's working fine. Naturally I voided the warranty, but since the warranty requires the end user to pay for the privilege of waiting 4-6 weeks to get the device back, I consider the warranty less than useful.
     

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