720/730 920/930 Battery Replacement Tutorial

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Dec 28, 2007
Colorado, USA
TomTom Model(s)
GO720, GO740, GO 1535, Via 1535, Via 1605, GO 52, GO 600, GO 620, GO 630, GO Discover, TomTom Bridge
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.

Important Note

I have had 3 reports of users breaking the flex circuit connector during removal of the display.

Some users have reported success in swapping batteries without removing the cable. I would warn that the cable is somewhat delicate, and twisting/pulling this cable isn't good for it. If you avoid removing the cable from the connector, PLEASE use restraint when moving the display half around.

If you do choose to disconnect the flex cable, be aware that the brown locking lever tabs are flat when the connection is closed, and the photo included in the PDF shows the tabs already in their fully open position, about 30~45 degrees up. That is as far as it needs to be lifted to release the cable. It seems some have been trying to lift the tabs even higher (perhaps thinking they should point straight up) and have broken the white connector as a result. Don't do that! Raise tabs only until it releases from the flat position, and gently pull the cable out away from 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.

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