Thread: 720/730 920/930 Battery Change

720/730 920/930 Battery Change
1x Attached PDF File

TomTom GO x20 (and probably x30) Battery Replacement

First, you’ll need to procure a matching Lithium Polymer battery. I’ve run across others of the
same type on the net, but have noted odd numbers of wires and mismatched connectors. I
purchased the “real deal” at BatteryShip.com under their part number AHL03713100. They
don’t seem to realize that they have more than just a GO920/920T battery. Trust me, the 720
and 720T use exactly the same pack. Each uses the same 3 pin connector.

As I have yet to own either of these in the x30 flavor, I can’t say with absolute certainty that the
pack is identical in all respects, but I’ve heard nothing to the contrary.

If you purchase from BatteryShip.com, you’ll also receive a couple of torx head wrenchs and a
plastic tool that looks like you’d use it to remove miniature bicycle tires. The miniature slot and
philips screwdrivers won’t be needed unless your unit was built with different screws than mine.
Come to think of it, I believe my original 720 used philips screws.

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

Sorry for the quality of the photography. 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?) and 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

You may find that the small tool provided with the battery helps to get a sticky main unit
separated from the 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.