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Thread: 720-730 Battery Replacement with PICTURES *HOW TO*

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    ChillyCat is offline Command Sergeant Major
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    720-730 Battery Replacement with PICTURES *HOW TO*

    Step #1 – Remove Antenna Plug and Screws


    Start by flipping the unit on its face on a soft surface.
    Remove the antenna plug with your fingers, and remove the two screws indicated...



    Step #2 – Separate Display from Case



    Using the screwdriver or something slightly larger, push on the threaded insert where
    the screw had been until you begin to see the front of the unit move away from the case.
    Move back and forth between the two sides. It may be a bit sticky.

    Carefully pull the top of the unit away from the case. The bottom of the unit is held
    into the case mechanically using a little hook mechanism. Don’t force the separation.
    Lift the unit away from the hook on the bottom during separation.
    Step #3 – Remove Display Unit Flex Cable and Mic Cable, and Split Unit



    The amber colored plastic with the copper traces in it is the flex circuit.
    On my unit, there was a strip of black tape covering the connector.
    If there, you’ll need to peel that black tape off first.




    Fortunately, I got a good side view of the latch that holds the flex circuit into the connector. Raise the latch tabs as shown. Once done, the flex circuit will slip right out of the connector.
    Remove the mic connector (or is it the light sensor?) an
    d you will have now split the unit into two freestanding pieces.


    Step #4 – Remove Screws Securing Main Unit to Case



    Remove the 4 indicated screws. If you have an SD card installed, this would be a good time to remove that as well, if you haven’t already...


    Step #5 – Separate Main Unit from Case


    Exercise care when separating the unit – the speaker connector must be unplugged as well.


    Step #6 – Remove the Lithium Ion Battery Connector and Remove Battery



    Disconnect the 3 pin connector as shown. Sorry about the focus – I didn’t have much light, so there isn’t much depth of field in many of these shots.

    Step #7 – Separate Battery from Circuit Board


    OK – this is where it gets hairy. If you are the nervous type, this would be a good place to stop. The battery is likely stuck onto the circuit board with some seriously aggressive adhesive .. some sort of contact cement material. It will be necessary to PRY the battery away from the circuit board. I started with the small tool provided with the battery, but found it inadequate to the task.

    Be aware that there are no components mounted under the battery, so use of a very thin screwdriver may (as it did for me) help you out a great deal – but you MUST use it carefully. You don’t want to scratch any of the copper traces from the back side of the board. I had bent the battery pack up a bit by the time it was finally released from the board, but hey – the battery is what’s expendable here.
    Step #8 – Apply Adhesive and Install New Battery



    Now while I’d be the first to argue that the adhesive TomTom is using might be a bit of overkill, it’s there for a very good reason. You don’t want your new battery rattling around inside the case. The remaining adhesive on the board isn’t enough to hold the new battery, so I opted for 4 dabs of silicone seal / adhesive to hold down my new battery. Once the dabs were in place, I carefully set the battery back down on the board and attached the connector. I used clear silicone, so it’s not as easy to see as it might have been. White, clear – doesn’t matter.

    The new wire was a good bit longer than the original, so I tucked the excess out of the way on the left side of the battery.

    Step #9 & etc. Reverse Everything


    I noticed something during disassembly and reassembly that gave me pause. There is a small round lug attached to the black wire under one of the screws. The metal of the lug comes perilously close to components underneath. Be SURE that it is bent up just a tiny bit so that it CANNOT touch the parts underneath.




    l
    Last edited by jarkita; 15th June 2010 at 15:18. Reason: moved to Tutorials section

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