Translation from Felix : "Do not remove solder! Just heat it up and put pressure on the battery. Soldering point JP1 not necessary. Only R6 or negative pole"

This is the most difficult part but it can be done once one understands how the tabs that need to be unlocked are designed and located. The difficulty is in seeing the tabs -- they are black - and especially the way they lock in, on the body.

There are two tabs - one each side - built on the internal frame holding the battery and electronic circuitry. They are pushing towards the outside, and each locks inside a recessed hole on the internal side of the toothbrush body.

They are most effectively unlocked by going deeper with the spudger and unlocking them by going behind them and hooking them from below, going in from the top opening. IMPORTANT NOTE The tabs need to be PUSHED from the outside TOWARDS the inside of the unit, i.e. towards the chassis that holds the battery and electronics. Trying to pushing the external toothbrush shaft from above will only damage the mechanism. The only way - on this latest Sonicare model- is to unlock these two black tabs.

Translation from German friend/contributor which was helpful: "The instructions are a bit misleading in step 6, there are only 2 soldering points, the battery only has 2 soldering tags as you can see. One at F1, the other at R6 and JP1. The bottom arrow in the picture pointing to JP1 is wrong. I recommend completely removing the solder with a desoldering pump with a silicone tip because the battery is firmly clamped in a plastic socket and is difficult to remove only by heating the solder and there is also an IC right next to the lower soldering point. You should be very careful when soldering."