Looking on the BB troubleshooting guide, we can see that the error is related to a bad battery, but it typically isn’t solved by simply replacing the battery. Here I will show you how to fix the problem and I will also comment a little bit about what to me appears as an obvious design fault. The problem is due to a broken connection between the battery connector and the mainboard.
To fix this error you will not need to buy any replacement part, unless the battery connector itself is damaged; however, you will need some tools:
- Soldering iron with a fairly fine tip
- Leaded solder
- (recommended, not strictly necessary) hot air soldering station and leaded solder paste
After disassembling my friend’s Q10, I immediately noticed that the battery connector was wobbling a fair bit, so I tried moving it back and forth with a pair of pliers and it just completely came off the board. Also, while the two external pads (VBATT and GND) just broke at the solder joint, the two inner pads had the copper completely ripped away from the PCB. Fixing ripped pads would typically require massive rework and fiddling around with a multimeter to try and find a point where the missing pads were connected. But, luckily, I was able to find a picture online showing the connection between the battery connector pads and four test pins placed near the connector itself. Below I have redrawn it a bit better.
Now, since the two external pads were still on the board, probably because filled with vias to connect to the inner power planes, I decided to partially reflow the broken connector using a hot air gun and some solder paste, and then fix the two inner pads with a couple of short jumper wires, as in the picture below, soldering them to the back of the pogo pins, because it is the most accessible place.
The fix itself required less than 15 minutes, and I was able to close back the case by just cutting a small piece of plastic with a pair of snippers.
However, in my opinion, using a surface mount battery connector is a tremendous design flaw: solder joints do not provide enough shear strength and in the event of the phone falling on the ground the weight of the battery can be enough to break the joints. Having two lateral through hole pins would have solved this issue entirely.